build: Add QCOM target-specific config

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

Change-Id: I736c10a5e7e1f3d1e0de9e60f29b60add276f151

Conflicts:
	core/config.mk
Revert "have reposync use all available cpu threads"

*Whenever someone is repo syncing on our buildbox, it hogs
 all of the cpu to the point of literally not being able to
 do anything until the repo sync is finished.

This reverts commit aa22a02efbfcbf9a8479a2dcbc5f8ff713b36b5a.
Merge branch 'kitkat' of https://github.com/AOKP/build into kitkat