gralloc: Change private usage flags from enums to defines

1. It helps in checking gralloc private usage flags at compile time.
2. Define GRALLOC_MODULE_PERFORM_GET_UBWC_FLAG to enable client to
   query the value of "PRIV_FLAGS_UBWC_ALIGNED" flag at run time.
3. Add ADRENO_PIXELFORMAT_NV12_EXT in defined Adreno Pixel formats
   to fix NV12_UBWC HAL pixel format conversion to Adreno format.

Change-Id: I78ccac98f1bd1bfbd2aa596ceb7a293f3d2e5f6e
4 files changed