Normalize MAKEDIR, ONF_MAKEDIR and ONF_MAKE

Change-Id: I3908c0738dbbed180d62dc0f4ba656226035ba5a
diff --git a/makefiles/gerrit/include.mk b/makefiles/gerrit/include.mk
index 54e5895..5ae76a4 100644
--- a/makefiles/gerrit/include.mk
+++ b/makefiles/gerrit/include.mk
@@ -18,7 +18,7 @@
 ##--------------------##
 ##---]  INCLUDES  [---##
 ##--------------------##
-include $(MAKEDIR)/gerrit/help.mk
+include $(ONF_MAKEDIR)/gerrit/help.mk
 
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