hwc: Rename libexternal to serve HDMI as primary or external

This change will make is easier to build new functionality
applicable to both HDMI scenarios.

Change-Id: I417184568cb65a49c2ccb4199aff313ae2ee9b24
diff --git a/libhwcomposer/hwc_mdpcomp.cpp b/libhwcomposer/hwc_mdpcomp.cpp
index 072eda3..d52955d 100644
--- a/libhwcomposer/hwc_mdpcomp.cpp
+++ b/libhwcomposer/hwc_mdpcomp.cpp
@@ -19,7 +19,7 @@
 #include <math.h>
 #include "hwc_mdpcomp.h"
 #include <sys/ioctl.h>
-#include "external.h"
+#include "hdmi.h"
 #include "qdMetaData.h"
 #include "mdp_version.h"
 #include "hwc_fbupdate.h"