DevicePolicyManager get factory MAC

Since MAC randomization will be randomized by default in Q,
which means the current MAC could change arbitrarily, the
existing API need to be modified to always get the factory MAC.

Bug: 111634904
Test: atest DevicePolicyManagerTest
Change-Id: I91a150fe4439ecef3836abb3c1ed087837a5fc67
1 file changed