py: Fix check of small-int overflow when parsing ints.

Also unifies use of SMALL_INT_FITS macro across parser and runtime.
diff --git a/py/runtime.c b/py/runtime.c
index f487807..a9d5746 100644
--- a/py/runtime.c
+++ b/py/runtime.c
@@ -413,7 +413,7 @@
                     goto unsupported_op;
             }
             // TODO: We just should make mp_obj_new_int() inline and use that
-            if (MP_OBJ_FITS_SMALL_INT(lhs_val)) {
+            if (MP_SMALL_INT_FITS(lhs_val)) {
                 return MP_OBJ_NEW_SMALL_INT(lhs_val);
             } else {
                 return mp_obj_new_int(lhs_val);