all: Raise exceptions via mp_raise_XXX

- Changed: ValueError, TypeError, NotImplementedError
  - OSError invocations unchanged, because the corresponding utility
    function takes ints, not strings like the long form invocation.
  - OverflowError, IndexError and RuntimeError etc. not changed for now
    until we decide whether to add new utility functions.

esp8266/modmachine.c

@@ -59,8 +59,7 @@ STATIC mp_obj_t machine_freq(mp_uint_t n_args, const mp_obj_t *args) {
         // set
         mp_int_t freq = mp_obj_get_int(args[0]) / 1000000;
         if (freq != 80 && freq != 160) {
-            nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
-                    "frequency can only be either 80Mhz or 160MHz"));
+            mp_raise_ValueError("frequency can only be either 80Mhz or 160MHz");
         }
         system_update_cpu_freq(freq);
         return mp_const_none;