Change mp_obj_type_t.name from const char * to qstr.

Ultimately all static strings should be qstr.  This entry in the type
structure is only used for printing error messages (to tell the type of
the bad argument), and printing objects that don't supply a .print method.

py/objnone.c

@@ -25,7 +25,7 @@ STATIC mp_obj_t none_unary_op(int op, mp_obj_t o_in) {
 
 const mp_obj_type_t none_type = {
     { &mp_const_type },
-    "NoneType",
+    .name = MP_QSTR_NoneType,
     .print = none_print,
     .unary_op = none_unary_op,
 };