Delay start of mediaswcodec until after APEX is mounted

The swcodecs are all loaded from apex.

bug: 123166478
Change-Id: Ib7c4ac54aedb596fb7c6fff9016ae989955dd374
test: builds; boots and c2 swcodec runs normally
diff --git a/services/mediacodec/mediaswcodec.rc b/services/mediacodec/mediaswcodec.rc
index dfe3381..3549666 100644
--- a/services/mediacodec/mediaswcodec.rc
+++ b/services/mediacodec/mediaswcodec.rc
@@ -2,5 +2,6 @@
     class main
     user mediacodec
     group camera drmrpc mediadrm
+    updatable
     ioprio rt 4
     writepid /dev/cpuset/foreground/tasks