build: Add QCOM target-specific config

 * Needed to support global DirectTract config on legacy targets
 * Let's also eliminate some boilerplate

Change-Id: I736c10a5e7e1f3d1e0de9e60f29b60add276f151
Signed-off-by: iceandfire <arhamjamal@gmail.com>

Conflicts:
	core/config.mk
Merge branch 'kitkat' of https://github.com/TeamHorizon/android_build into kitkat