Initialize the RTT pipes if incoming calls request

Initialize the RTT pipes if either the UI setting is on or if the
incoming call requests RTT. Depending on carrier requirements there's a
chance that RTT could be turned on later if either is true.

Change-Id: Iaf98c6e1ae43167a40b70dc47a15f1c742ba2b7f
Fixes: 74563205
Test: manual