Fix -Werror on 64-bit builds

Add another static_cast to avoid an error on 64-bit builds

Change-Id: I62fb2c67766c4aab70d9d1834f255d06ff82dd8d
(cherry picked from commit 116c7a113c)

libs/ui/GraphicBuffer.cpp

@@ -116,7 +116,7 @@ void GraphicBuffer::free_handle()
 }
 
 status_t GraphicBuffer::initCheck() const {
-    return mInitCheck;
+    return static_cast<status_t>(mInitCheck);
 }
 
 void GraphicBuffer::dumpAllocationsToSystemLog()