gralloc: Add HAL_PIXEL_FORMAT_BGR_565 format

- Define new format in gralloc_priv.h header
- Add support for HAL_PIXEL_FORMAT_BGR_565 while allocating buffers

CRs-fixed: 904907

Change-Id: I2cf3cdcfc5c89b11abc4ceb4daba77a5123ecf67
diff --git a/libgralloc/gralloc_priv.h b/libgralloc/gralloc_priv.h
index 2601953..6ddee83 100755
--- a/libgralloc/gralloc_priv.h
+++ b/libgralloc/gralloc_priv.h
@@ -105,6 +105,7 @@
 #define HAL_PIXEL_FORMAT_BGRX_8888               0x112
 #define HAL_PIXEL_FORMAT_NV21_ZSL                0x113
 #define HAL_PIXEL_FORMAT_YCrCb_420_SP_VENUS      0x114
+#define HAL_PIXEL_FORMAT_BGR_565                 0x115
 #define HAL_PIXEL_FORMAT_INTERLACE               0x180
 
 //v4l2_fourcc('Y', 'U', 'Y', 'L'). 24 bpp YUYV 4:2:2 10 bit per component