Selinux-MediaDRM server : Reduce permissions as /dev/nvmap is not used

Moved from using nvmap shared buffers to ash_mem as selinux
permissions on /dev/nvmap (a.k.a gpu_device) will defeat the
purpose of mediaserver & mediaDrmServer split from a security
point of view.

This needs to be merged after :Omx & oemcrypto changes.

https://partner-android-review.googlesource.com/#/c/591874/
https://partner-android-review.googlesource.com/#/c/591667/

Signed-off-by: Parag Mehendale <pmehendale@nvidia.com>
Bug: 26780693
Change-Id: Ic4cbef72923ba95b3b4749336b9812e28dccc8c0
diff --git a/sepolicy/mediadrmserver.te b/sepolicy/mediadrmserver.te
index 4c594ee..cd402d4 100644
--- a/sepolicy/mediadrmserver.te
+++ b/sepolicy/mediadrmserver.te
@@ -1,2 +1 @@
 allow mediadrmserver video_device:chr_file rw_file_perms;
-allow mediadrmserver gpu_device:chr_file rw_file_perms;