overlay: Add support for decimation.

Add support for decimation on top of what MDP can downscale,
because decimation can have quality issues.
B-family MDP downscale of 1/4, plus decimation of 1/16 can let
us have a total downscale of 1/64.

Also decimate by 2 (min) if width is greater than what layer mixer
supports and is not handled by the client.

Change-Id: I3b7c4bf321c7561bd98206ad118f4ac1ee2879ae
diff --git a/libhwcomposer/hwc_fbupdate.cpp b/libhwcomposer/hwc_fbupdate.cpp
index b8e6976..9f91a99 100644
--- a/libhwcomposer/hwc_fbupdate.cpp
+++ b/libhwcomposer/hwc_fbupdate.cpp
@@ -21,6 +21,9 @@
 #define DEBUG_FBUPDATE 0
 #include <gralloc_priv.h>
 #include "hwc_fbupdate.h"
+#include "mdp_version.h"
+
+using namespace qdutils;
 
 namespace qhwc {