ports: Consolidate inclusion of umachine module in built-ins.

The inclusion of `umachine` in the list of built-in modules is now done
centrally in py/objmodule.c.  Enabling MICROPY_PY_MACHINE will include this
module.

As part of this, all ports now have `umachine` as the core module name
(previously some had only `machine` as the name).

Signed-off-by: Damien George <damien@micropython.org>

py/objmodule.c

@@ -219,6 +219,9 @@ STATIC const mp_rom_map_elem_t mp_builtin_module_table[] = {
     #if MICROPY_PY_LWIP
     { MP_ROM_QSTR(MP_QSTR_lwip), MP_ROM_PTR(&mp_module_lwip) },
     #endif
+    #if MICROPY_PY_MACHINE
+    { MP_ROM_QSTR(MP_QSTR_umachine), MP_ROM_PTR(&mp_module_machine) },
+    #endif
     #if MICROPY_PY_UWEBSOCKET
     { MP_ROM_QSTR(MP_QSTR_uwebsocket), MP_ROM_PTR(&mp_module_uwebsocket) },
     #endif