sepolicy: ashmem entry point for libcutils

This duplicated ashmem device is intended to replace ashmemd.

Ashmem fd has a label of the domain that opens it. Now with ashmemd
removed, ashmem fds can have labels other than "ashmemd", e.g.
"system_server". We add missing permissions to make ashmem fds usable.

Bug: 139855428
Test: boot device
Change-Id: Iec8352567f1e4f171f76db1272935eee59156954
5 files changed