Revert "gralloc: Allow legacy devices to use PMEM for ADSP (camera)"

This reverts commit 857510fce43679f49b22cfa55307f80d81288a1c.
gralloc: Allow legacy devices to use PMEM for ADSP (camera)
Partially bring back PMEM support for legacy devices having proprietary camera
libraries stuck in PMEM. This change allows these devices to continue using
PMEM for the camera, and ION for everything else.
Change-Id: I1382381134db21435ca725d0e2c2b3194da16f38