gralloc: Add warning for an unsupported DRM format.

HAL_PIXEL_FORMAT_RGBA_FP16 no longer issues an error, added a new case to issue a warning instead

Change-Id: I24645d829df6d904fefd981d75d5c632722d6a1d
CRs-Fixed: 2906854
diff --git a/gralloc/gr_utils.cpp b/gralloc/gr_utils.cpp
index e56a81e..d955912 100644
--- a/gralloc/gr_utils.cpp
+++ b/gralloc/gr_utils.cpp
@@ -1909,6 +1909,9 @@
     case HAL_PIXEL_FORMAT_YV12:
       *drm_format = DRM_FORMAT_YVU420;
       break;
+    case HAL_PIXEL_FORMAT_RGBA_FP16:
+      ALOGW("HAL_PIXEL_FORMAT_RGBA_FP16 currently not supported");
+      break;
     default:
       ALOGE("Unsupported format %d", format);
   }