Add a comment in TEST_MAPPING that ath_config has to be updated

Bug: N/A
Test: N/A
Change-Id: Ibcbe61aed181cfed098e1b0f9d9be3a14c6fd63a
diff --git a/TEST_MAPPING b/TEST_MAPPING
index cc413b4..e2cf9a5 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -1,3 +1,5 @@
+// When adding or removing tests here, don't forget to amend _all_modules list in
+// wireless/android/busytown/ath_config/configs/prod/avf/tests.gcl
 {
   "avf-presubmit": [
     {
@@ -98,3 +100,5 @@
     }
   ]
 }
+// When adding or removing tests here, don't forget to amend _all_modules list in
+// wireless/android/busytown/ath_config/configs/prod/avf/tests.gcl