audio_route: Add APIs to update mixer based on path

audio_route_apply_and_update_path
audio_route_reset_and_update_path

These routines allows updating the mixer controls for
just the specified path. The controls will be updated
in the order listed in the XML file.

Change-Id: If193bc047ccbb8c6497926d6181c5c4541a9d6aa
CRs-Fixed: 581453
[1/3] AudioEffects: Add center frequency param to bassboost

Change-Id: Ia47a3f679a82392232b33b72e8dbd3b2545ee109
[2/3] audio_effects: Add a stereo widening effect

Change-Id: I0dd68fef857e8a031f52a63a81c642cb930419c6