gta4xl-common: specify encryption format for adoptable storage

Change-Id: I781d803627330d81b4011321ca721ff4abba4339
diff --git a/vendor.prop b/vendor.prop
index ed972db..8db8b09 100644
--- a/vendor.prop
+++ b/vendor.prop
@@ -1,3 +1,6 @@
+## Adoptable Storage
+ro.crypto.volume.options=aes-256-xts
+
 ## Audio
 audio.offload.min.duration.secs=30
 aaudio.mmap_policy=2