build: Use common name for QCOM 7K boards.

This is needed to build QCOM HAL without external modifications. The
device would now have to specify msm7x27 or msm7x30 instead of
specifying the full name.

Patch Set 2: Add msm7x27a into the list.

Change-Id: I25018e397b5aad27fab5244731a574ae86752e17
Merge "build: Use common name for QCOM 7K boards." into android-4.4