Added telephony display info support

Added the new APIs allowing clients like System UI to display
network icons correctly based on the provided telephony display
info.

Test: Telephony sanity tests
Bug: 148540139
Change-Id: I4dfb6eb7a313539e0565a4239d555426f12e503e
Merged-In: I4dfb6eb7a313539e0565a4239d555426f12e503e