py, unix: Allow to compile with -Wunused-parameter.

See issue #699.
diff --git a/py/objdict.c b/py/objdict.c
index 900ecf4..e97f30e 100644
--- a/py/objdict.c
+++ b/py/objdict.c
@@ -74,6 +74,7 @@
 }
 
 STATIC mp_obj_t dict_make_new(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
+    (void)type_in;
     mp_obj_t dict = mp_obj_new_dict(0);
     if (n_args > 0 || n_kw > 0) {
         mp_obj_t args2[2] = {dict, args[0]}; // args[0] is always valid, even if it's not a positional arg
@@ -446,6 +447,7 @@
 }
 
 STATIC void dict_view_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+    (void)kind;
     assert(MP_OBJ_IS_TYPE(self_in, &dict_view_type));
     mp_obj_dict_view_t *self = self_in;
     bool first = true;