Report graphics_device accesses by system_server or mediaserver.

See if we can remove these allow rules by auditing any granting
of these permissions.  These rules may be a legacy of older Android
or some board where the gpu device lived under /dev/graphics too.

Change-Id: I5c5d99ca97402de5196d9b6dfd249294f4d95baa
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>