omni: Guard init_daemon_domain(mkfs).

This triggers a neverallow on full treble builds.

Change-Id: I7169d5a940ab2f993a74b4d1471eb2931555bf74
diff --git a/sepolicy/mkfs.te b/sepolicy/mkfs.te
index fe7c61b..6b35e95 100644
--- a/sepolicy/mkfs.te
+++ b/sepolicy/mkfs.te
@@ -1,7 +1,9 @@
 type mkfs, domain;
 type mkfs_exec, exec_type, file_type;
 
-init_daemon_domain(mkfs)
+not_full_treble(`
+   init_daemon_domain(mkfs);
+')
 
 # Allow formatting userdata or cache partitions
 allow mkfs block_device:dir search;