sepolicy: add diag device as mlstrustedobject

All services are allowed access to diag device except untrusted_app.
MLS restrition prevent platform_app to access diag device.
Make diag device as trusted object for apps to access it.

Change-Id: I650de7f7da04369e493d6d84f481fb544e3339fa
CRs-Fixed: 913007
1 file changed