gralloc: Add backwards-compatible gralloc

 * Upstream version of gralloc is beginning to diverge and requires
   changes in both the kernel and camera HAL to use.
 * We need the new HAL to support new GPU drivers and a new device
   family, so split out a libgralloc-compat version which will
   be used by default in order to not break current devices.
 * Targets can enable the new HAL with TARGET_HAVE_NEW_GRALLOC.
 * Also add a new flag which can be used to disable the COMPAT_PERFORM
   flag if needed. This is on by default.

Change-Id: Ie4c51c65e48323f9819164478a5afbf8abb99223