ALSA: usb-audio: us144mkii: Implement audio capture and decoding

This patch adds the full audio capture data path. It allocates and
manages bulk URBs to receive audio data from the device.

The incoming data is in a custom multiplexed format. A workqueue is
used to offload the decoding process from the interrupt context. The
`capture_urb_complete` handler copies raw data into a ring buffer and
schedules the work. The `tascam_capture_work_handler` then reads from
this buffer, decodes the data into standard S32_LE samples, and copies
it to the ALSA capture buffer.

The PCM trigger is updated to manage the submission of capture URBs,
and the feedback handler now also advances the capture stream pointer
to keep it synchronized with playback.

Signed-off-by: Šerif Rami <ramiserifpersia@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20250814172222.9448-5-ramiserifpersia@gmail.com