Fix cpplint's whitespace warnings.

Change-Id: I16b69d773e59b49e8e30227b5aa5cb1959a8930f
diff --git a/Android.mk b/Android.mk
index a1124ce..59a4f50 100644
--- a/Android.mk
+++ b/Android.mk
@@ -250,7 +250,7 @@
 cpplint-art:
 	./art/tools/cpplint.py \
 	    --filter=-whitespace/comments,-whitespace/line_length,-build/include,-build/header_guard,-readability/streams,-readability/todo,-runtime/references \
-	    art/src/*.h art/src/*.cc
+	    $(ANDROID_BUILD_TOP)/art/src/*.h $(ANDROID_BUILD_TOP)/art/src/*.cc
 
 ########################################################################