Add missing attribute to compatibility file.

untrusted_app_visible_hwservice was an attribute that was meant to
give partners time to add their HALs to AOSP.  It was removed from mr1
and so needs to be accounted for in the compatibility mapping.

Bug: 64321916
Test: Builds with treble policy tests.
Change-Id: I359a842083016f0cf6c9d7ffed2116feb9e159c6