So far, tablets with telephony have been inheriting from
common_full_phone.mk, but that's not really proper because
such makefile now enables one-handed mode support
(setting prop ro.support_one_handed_mode to true).
Fix this by creating new makefiles that can be used also
to include more tablet-specific configs moving forward.
Change-Id: I90c22badb17911ef5e873299d986204718300e6c