Gralloc/Camera3: Support new HAL_PIXEL_FORMAT_YCbCr_420_888 format

Enable flexible YUV format buffers from the camera.

 - Add gralloc alloc support for YCbCr_420_888, mapped to NV21
 - Add gralloc lock_ycbcr method
 - Add new format to list supported by camera HAL
 - Fix minor compilation warnings

Bug: 8734880
Change-Id: I68a8cc126985c7d5ae100a87b31c60ee59074cd3
4 files changed