Remove mediaserver sysfs write permissions.

Mediaserver no longer appears, and maybe never did, need write
permission to sysfs files.
commit: 1de9c492d1343f7c92b4a7d6aa8da82c97bbf7d8 added auditing to
make sure this is the case, and such access has not been observed.
Remove the permissions and the associated auditallow rule to further
confine the mediaserver sandbox.

Bug: 22827371
Change-Id: I44ca1521b9791db027300aa84e54c074845aa735
1 file changed