audio policy: fix call routing via audio patch

The audio source used to control the call RX path must be tagged as
internal so that the corresponding audio patch is not realized with a
software audio patch because of the lack of gain controller on sink device.

Voice call volume is controlled via setVoiceVolume() HAL API and not
track volume control or device gain control

Bug: 302519079
Test: make
Change-Id: Ie9217f1be1bf127915d6bdf42d5de0834966b9d2