hwc: RGB888 is considered as a VIDEO type

For mpq8092, RGB888 is the output video format, so need to make
it a video buffer type, so that VIG pipe gets allocated for
it. Another reason is that GPU cannot process RGB888, so marking
it as a VIDEO layer will ensure that it will get picked by MDP.

Change-Id: I5d1812a70f5e4d1fb7448d0a145a15c07c6fc188

libgralloc/gpu.cpp

@@ -173,6 +173,9 @@ void gpu_context_t::getGrallocInformationFromFormat(int inputFormat,
 {
     *bufferType = BUFFER_TYPE_VIDEO;
 
+    if (inputFormat == HAL_PIXEL_FORMAT_RGB_888)
+        return;
+
     if (inputFormat <= HAL_PIXEL_FORMAT_sRGB_X_8888) {
         // RGB formats
         *bufferType = BUFFER_TYPE_UI;