Remove fixed grant of READ_PHONE_STATE and cleanup

No longer grant READ_PHONE_STATE as a fixed permission to all apps
holding READ_PRIVILEGED_PHONE_STATE. Also clean up the previous grants
by un-fixing the permission if the app requests it in the manifest, and
removing it altogether if the app only requests READ_PRIV.

Bug: 183537857
Test: manual -- prepare two system apps, one with READ_PRIV and
READ_PHONE and one with only READ_PRIV, then go through the upgrade flow
with this CL.

Change-Id: Id1fac0f9f4391857f46c7109eadafd60420b279d