Temporarily dontaudit ueventd->tmpfs access

This is the only blocker for SELinux denial test on microdroid. Rather
than consuming more time, this temporarily suppresses the audit message
to turn on the test.

Bug: 193118220
Test: atest MicrodroidHostTestCases -c
Change-Id: Id703107cbaae42352bebe34d0a6373f0701c0f6f
1 file changed