serranoltexx: Remove MMS overlay

 * We have a multi-carrier common overlay now.

Change-Id: Ida946b2a9e4299a514e9b3c878e777c609c7fbed
Signed-off-by: Willi Ye <williye97@gmail.com>

Conflicts:
	overlay/packages/apps/Mms/res/xml/mms_config.xml