audio: Add 'encodedFormats' field to 'devicePort'

This is used to specify the list of codecs that the device
supports.

Bug: 120860184
Test: xmllint --noout --xinclude --schema \
      hardware/interfaces/audio/5.0/config/audio_policy_configuration.xsd \
      frameworks/av/services/audiopolicy/config/audio_policy_configuration*.xml

Change-Id: Ifb80afed7947dc2332a8188defa86db98851188e