MHF: Route call to correct HS in multi call scenario.

  - This change makes sure that audio routes back to correct
    headset in multi call scenario even though the other
    headset tries to answer or dial.
  - Ignore setting hf_idx for ATA/BLDN received from HS
    for a waiting call when an active/held call is already
    present.

Change-Id: I19949471d481bf911fda2222dc6d730d1a821b65
1 file changed