audiopolicy: Refactor AudioPolicyManager::updateCallRouting

The code of the function had almost identical paths for
Rx and Tx patches creation. Factored them out, now it's much
easier to see what is common, and what differs.

Test: audio in still present incoming and outgoing telephony calls
Change-Id: Ia02179513d76809e33c65b2dad465358acdbfc63
2 files changed