overlay: Request specific pipe type

Request driver for a specific pipe type instead of
notifying the type request using mdp flags.

Change-Id: I83fffc7c0e1f24d903b7dd6d52a58b87c70f3d4f
diff --git a/liboverlay/overlay.h b/liboverlay/overlay.h
index 99186db..c8f68b0 100644
--- a/liboverlay/overlay.h
+++ b/liboverlay/overlay.h
@@ -179,6 +179,8 @@
     static void initScalar();
     /* Destroys the scalar object using libscale.so */
     static void destroyScalar();
+    /* Sets the pipe type RGB/VG/DMA*/
+    void setPipeType(utils::eDest pipeIndex, const utils::eMdpPipeType pType);
 
     /* Just like a Facebook for pipes, but much less profile info */
     struct PipeBook {