IMS: Add logic for Pseudo DSDA support

- Added logic to support Pseudo DSDA in
  telephony that will handle BT / headset
  scenarios.

Change-Id: I80587d39c9152332d44321ab50f2235439a7753f
Issue: FP3-A13#56
CRs-Fixed: 2718074
(cherry picked from commit eb2cc1bedfc953105b8777299ce4949b64671f99)
4 files changed