drm_hwcomposer: fix spelling of "separate".

It is spelled "separate", not "seperate".

Change-Id: Id92d12aba42989a8a72e4596d425b2a9eea4e5ec
diff --git a/drmdisplaycompositor.h b/drmdisplaycompositor.h
index 7606740..a05284b 100644
--- a/drmdisplaycompositor.h
+++ b/drmdisplaycompositor.h
@@ -21,7 +21,7 @@
 #include "drmcomposition.h"
 #include "drmcompositorworker.h"
 #include "drmframebuffer.h"
-#include "seperate_rects.h"
+#include "separate_rects.h"
 
 #include <pthread.h>
 #include <memory>