drm_hwcomposer: fix spelling of "separate".

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

Change-Id: Id92d12aba42989a8a72e4596d425b2a9eea4e5ec
diff --git a/Android.mk b/Android.mk
index 810caac..ca94f4c 100644
--- a/Android.mk
+++ b/Android.mk
@@ -38,20 +38,20 @@
 
 LOCAL_SRC_FILES := \
 	drmresources.cpp \
-        drmcomposition.cpp \
-        drmcompositor.cpp \
-        drmcompositorworker.cpp \
+	drmcomposition.cpp \
+	drmcompositor.cpp \
+	drmcompositorworker.cpp \
 	drmconnector.cpp \
 	drmcrtc.cpp \
-        drmdisplaycomposition.cpp \
-        drmdisplaycompositor.cpp \
+	drmdisplaycomposition.cpp \
+	drmdisplaycompositor.cpp \
 	drmencoder.cpp \
 	drmmode.cpp \
 	drmplane.cpp \
 	drmproperty.cpp \
 	glworker.cpp \
 	hwcomposer.cpp \
-	seperate_rects.cpp \
+	separate_rects.cpp \
 	virtualcompositorworker.cpp \
 	vsyncworker.cpp \
 	worker.cpp