gralloc: ifdef allocSize with QCOM_BSP

Matching changes in native and libhardware.

Change-Id: Ifd1f3d65aad743a55193863d9f8a1b36a88435a6

Revert commit 35be606bd78b0bff3164fdc9f53aa4c0e2bed21e
Conflicts:
	common.mk
	libgralloc/gpu.cpp