drm_hwcomposer: update #include's for drm_hwcomposer.h

That's the second most important part of renaming a file.

Change-Id: If9280f3b360389ef17b798e162a9c3b0c0a3133b
diff --git a/drmdisplaycomposition.h b/drmdisplaycomposition.h
index 69324fd..e79466e 100644
--- a/drmdisplaycomposition.h
+++ b/drmdisplaycomposition.h
@@ -17,7 +17,7 @@
 #ifndef ANDROID_DRM_DISPLAY_COMPOSITION_H_
 #define ANDROID_DRM_DISPLAY_COMPOSITION_H_
 
-#include "drm_hwcomposer.h"
+#include "drmhwcomposer.h"
 #include "drmcrtc.h"
 #include "drmplane.h"
 #include "glworker.h"