py: Use mp_raise_TypeError/mp_raise_ValueError helpers where possible.

Saves 168 bytes on bare-arm.
diff --git a/py/obj.c b/py/obj.c
index c065a3b..4b5fe25 100644
--- a/py/obj.c
+++ b/py/obj.c
@@ -229,7 +229,7 @@
         return mp_obj_int_get_checked(arg);
     } else {
         if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
-            mp_raise_msg(&mp_type_TypeError, "can't convert to int");
+            mp_raise_TypeError("can't convert to int");
         } else {
             nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                 "can't convert %s to int", mp_obj_get_type_str(arg)));
@@ -279,7 +279,7 @@
         return mp_obj_float_get(arg);
     } else {
         if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
-            mp_raise_msg(&mp_type_TypeError, "can't convert to float");
+            mp_raise_TypeError("can't convert to float");
         } else {
             nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                 "can't convert %s to float", mp_obj_get_type_str(arg)));
@@ -310,7 +310,7 @@
         mp_obj_complex_get(arg, real, imag);
     } else {
         if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
-            mp_raise_msg(&mp_type_TypeError, "can't convert to complex");
+            mp_raise_TypeError("can't convert to complex");
         } else {
             nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                 "can't convert %s to complex", mp_obj_get_type_str(arg)));
@@ -328,7 +328,7 @@
         mp_obj_list_get(o, len, items);
     } else {
         if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
-            mp_raise_msg(&mp_type_TypeError, "expected tuple/list");
+            mp_raise_TypeError("expected tuple/list");
         } else {
             nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                 "object '%s' is not a tuple or list", mp_obj_get_type_str(o)));
@@ -342,7 +342,7 @@
     mp_obj_get_array(o, &seq_len, items);
     if (seq_len != len) {
         if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
-            mp_raise_msg(&mp_type_ValueError, "tuple/list has wrong length");
+            mp_raise_ValueError("tuple/list has wrong length");
         } else {
             nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError,
                 "requested length %d but object has length %d", (int)len, (int)seq_len));
@@ -357,7 +357,7 @@
         i = MP_OBJ_SMALL_INT_VALUE(index);
     } else if (!mp_obj_get_int_maybe(index, &i)) {
         if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
-            mp_raise_msg(&mp_type_TypeError, "indices must be integers");
+            mp_raise_TypeError("indices must be integers");
         } else {
             nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                 "%q indices must be integers, not %s",
@@ -412,7 +412,7 @@
     mp_obj_t len = mp_obj_len_maybe(o_in);
     if (len == MP_OBJ_NULL) {
         if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
-            mp_raise_msg(&mp_type_TypeError, "object has no len");
+            mp_raise_TypeError("object has no len");
         } else {
             nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                 "object of type '%s' has no len()", mp_obj_get_type_str(o_in)));
@@ -453,7 +453,7 @@
     }
     if (value == MP_OBJ_NULL) {
         if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
-            mp_raise_msg(&mp_type_TypeError, "object does not support item deletion");
+            mp_raise_TypeError("object does not support item deletion");
         } else {
             nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                 "'%s' object does not support item deletion", mp_obj_get_type_str(base)));
@@ -468,7 +468,7 @@
         }
     } else {
         if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
-            mp_raise_msg(&mp_type_TypeError, "object does not support item assignment");
+            mp_raise_TypeError("object does not support item assignment");
         } else {
             nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                 "'%s' object does not support item assignment", mp_obj_get_type_str(base)));
@@ -502,7 +502,7 @@
 
 void mp_get_buffer_raise(mp_obj_t obj, mp_buffer_info_t *bufinfo, mp_uint_t flags) {
     if (!mp_get_buffer(obj, bufinfo, flags)) {
-        mp_raise_msg(&mp_type_TypeError, "object with buffer protocol required");
+        mp_raise_TypeError("object with buffer protocol required");
     }
 }