Add the list of possible ports for a device.
Pass the allowed devices in the routes.
Store the active port in the device.
Fixes enumeration of ports on devices with UCM.
Add a READONLY property flag to makr properties READONLY
Set the base_volume and volume_step in the acp device
Send the base volume and step as REAONLY properties. Use these
in pulse layer.
libacp is a port and wrapper around the pulseaudio card profile code.
It uses a set of templates for construct a card profile and mixer port
settings. It also has support for UCM when available for the hardware.