remove CONFIG_PLATFORM_MT53XX code

Signed-off-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>
remove CONFIG_PLATFORM_ACTIONS_* code

Signed-off-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>
remove CONFIG_PLATFORM_MN10300 code

Signed-off-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>