- Remove unused GRALLOC_USAGE_PRIVATE_PMEM flag. This flag is no
longer used.
- Flush ashmem region cache instead of Invalidating it.
(cherry picked from commit 12254ff74f5a97dcf5ded90f53e9d6fd0fa47b9c)
Change-Id: I92e4dcd8c89eb9ae0c0484f039d152b7bbb28bbe