all: Use mp_obj_malloc everywhere it's applicable.

This replaces occurences of

    foo_t *foo = m_new_obj(foo_t);
    foo->base.type = &foo_type;

with

    foo_t *foo = mp_obj_malloc(foo_t, &foo_type);

Excludes any places where base is a sub-field or when new0/memset is used.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>

py/objcell.c

@@ -64,8 +64,7 @@ STATIC const mp_obj_type_t mp_type_cell = {
 };
 
 mp_obj_t mp_obj_new_cell(mp_obj_t obj) {
-    mp_obj_cell_t *o = m_new_obj(mp_obj_cell_t);
-    o->base.type = &mp_type_cell;
+    mp_obj_cell_t *o = mp_obj_malloc(mp_obj_cell_t, &mp_type_cell);
     o->obj = obj;
     return MP_OBJ_FROM_PTR(o);
 }