gralloc4: lockYCbCr shouldn't return UNSUPPORTED

Bug: 150384131
Test: GraphicBuffer_test

Change-Id: I87876cf82e8e6250ac755792c2302bf511699758
diff --git a/libs/ui/Gralloc4.cpp b/libs/ui/Gralloc4.cpp
index 30c48c8..6fd4b80 100644
--- a/libs/ui/Gralloc4.cpp
+++ b/libs/ui/Gralloc4.cpp
@@ -364,7 +364,7 @@
     }
 
     *outYcbcr = ycbcr;
-    return static_cast<status_t>(Error::UNSUPPORTED);
+    return static_cast<status_t>(Error::NONE);
 }
 
 int Gralloc4Mapper::unlock(buffer_handle_t bufferHandle) const {