Add system_ext_$(ver).compat.cil

These are the system_ext counterpart of $(ver).compat.cil. They would
contain device specific compat rules that compliment $(ver).compat.cil,
which are the platform specific compat rules.

Bug: 183362912
Test: Add a $(ver).compat.cil under SYSTEM_EXT_PRIVATE_SEPOLICY_DIR and
  verify the file is installed under /system_ext/etc/selinux/mapping/
Change-Id: I2fb9b10bb3bcf112e33f504964fb705e3b63782b
2 files changed