audio policy: fix remote mic capture

commit 275e8e9de introduced a regression for platforms
overriding AudioPolicyManager::getDeviceForInputSource() method.

Fixed by defining specific non virtual methods when overiding would
break remote submix implementation.

Bug: 18736417.

Change-Id: Id4d0a6c48da987e6fb24422f2d61c7ab0fbfc921
2 files changed