Enable Async MTE in mtpd.

This change enables Async mode ARM MTE in mtpd on compatible
hardware and has no effect otherwise.

Bug: 181603044
Test: atest under system/netd/tests
Change-Id: I4405d2bc1254fc65ff044a878ac1abd99f7ffc89
diff --git a/Android.bp b/Android.bp
index 9efa325..f6c4960 100644
--- a/Android.bp
+++ b/Android.bp
@@ -48,4 +48,7 @@
         "-Werror",
     ],
     init_rc: ["mtpd.rc"],
+    sanitize: {
+        memtag_heap: true,
+    },
 }