Soundtrigger service: fix cross deadlock with audio policy service

Do not hold Module mutex when calling into audio policy manager to
avoid cross deadlock with audio poicy service mutex: Audio policy manager
can call into sound trigger service with its mutex held in methods like
stopInput().

Regression introduced by fix for b/64340921 commit f759b8c4

Bug: 64340921
Bug: 67310830
Test: repro steps in b/67310830
Merged-In: Ie50b2e7c55fe9828a3fd8de6b31eb4a492791583

Change-Id: Ie50b2e7c55fe9828a3fd8de6b31eb4a492791583