audiopolicy: port existing fixes to AudioPolicyManager

This is a squashed commit of the following fixes in
AudioPolicyManager. Only some parts of the fixes have been
ported as the custom audio policy has the other required
changes.

audiopolicy: Fix MT call delay
Change-Id: I790479eaad9d2d6fd4204cc4cb7698761c30f7cf

audiopolicy: support extended feature in audiopolicymanager
Change-Id: I1925339b591cd29f11a71c287a2e53c0627e9e62

audiopolicy: additional change for extended feature
Change-Id: I9bad6a294ddd7aee72f6f6a314666b892b730c8e

Change-Id: I7738d4b0ac11ee6d93bfd67e2553eae8518ff719