usb: device_next: new USB Audio 2 implementation

Introduce new USB Audio 2 implementation written from scratch. Main goal
behind new implementation was to perform entity configuration with
devicetree bindings, hiding the descriptor complexity from application.

Initial implementation is working at Full-Speed only. High-Speed support
will come later, but even at Full-Speed only this is viable replacement
for old stack USB Audio 1 class (USB Audio 1 is limited to Full-Speed by
specification, i.e. it is explicitly forbidden for USB Audio 1 device to
work at High-Speed).

Implemented is only absolute minimum set of features required for basic
implicit and explicit feedback samples. Only one sample frequency is
currently supported. Optional interrupt notifications are not supported.

Signed-off-by: Tomasz Moń <tomasz.mon@nordicsemi.no>
7 files changed