asan: update condition to work with multiple SANITIZE_TARGET values.

The goal is to enable SANITIZE_TARGET='address coverage', which
will be used by LLVMFuzzer.

Bug: 22850550
Change-Id: I953649186a7fae9b2495159237521f264d1de3b6
diff --git a/Android.mk b/Android.mk
index bb37712..0b9af0a 100644
--- a/Android.mk
+++ b/Android.mk
@@ -156,7 +156,7 @@
 include $(BUILD_SYSTEM)/base_rules.mk
 
 all_fc_files := file_contexts
-ifeq (address,$(strip $(SANITIZE_TARGET)))
+ifneq ($(filter address,$(SANITIZE_TARGET)),)
   all_fc_files := $(all_fc_files) file_contexts_asan
 endif
 all_fc_files := $(call build_policy, $(all_fc_files))