libaudiohal@aidl: Implement HW AV Sync operations

Implement DeviceHalAidl::getHwAvSync and
StreamHalAidl::setParameters for keyStreamHwAvSync.

Factor out common code in parameters filtering
from 'setParameters'.

Bug: 205884982
Test: m, launch CF w/AIDL enabled
Change-Id: I7af12f2425983a6b0ff8d828539722f314cbfcf2