Fix indirect misuse of $(my-dir).

Change-Id: I20a98a8e1378da3a53e6a6d599c8fc0100f7f87a
diff --git a/tools/preload/Android.mk b/tools/preload/Android.mk
index f325870..14a4547 100644
--- a/tools/preload/Android.mk
+++ b/tools/preload/Android.mk
@@ -20,4 +20,4 @@
 
 include $(BUILD_HOST_JAVA_LIBRARY)
 
-include $(call all-subdir-makefiles)
+include $(call all-makefiles-under,$(LOCAL_PATH))