Remove ENABLE_TREBLE from sepolicy.

Enabling/disabling sepolicy based on ENABLE_TREBLE is not granular
enough (ref: b/32978887 #4).

Bug: 32978887
Test: compiles, doesn't cause any additional denials on device. Nothing
depends on these things I'm removing.
Change-Id: I10acbde16e5e2093f2c9205ed79cd20caed7f44d