Include sdk-preprocess-files.mk before process sdk.atree

Bug: 336709919
Test: m sdk
Change-Id: Id0ad404f576478a6909eb440f3fb259606d57d02
diff --git a/core/Makefile b/core/Makefile
index a215d31..9845437 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -7605,6 +7605,7 @@
 sdk_dep_file := $(sdk_dir)/sdk_deps.mk
 
 ATREE_FILES :=
+include development/build/tools/sdk-preprocess-files.mk
 -include $(sdk_dep_file)
 
 # if we don't have a real list, then use "everything"