Set the container field of aconfig flags

Test: m
Bug: 312769710
Change-Id: Ib273d42785541476912bac98bb541283df0af5fb
diff --git a/media/aconfig/codec_fwk.aconfig b/media/aconfig/codec_fwk.aconfig
index 06aceeb..1475e15 100644
--- a/media/aconfig/codec_fwk.aconfig
+++ b/media/aconfig/codec_fwk.aconfig
@@ -3,6 +3,7 @@
 # !!! Please add flags in alphabetical order. !!!
 
 package: "android.media.codec"
+container: "system"
 
 flag {
   name: "aidl_hal_input_surface"