ASoC: usb: Fetch ASoC card and pcm device information

ASoC: usb: Fetch ASoC card and pcm device information

USB SND needs to know how the USB offload path is being routed.  This would
allow for applications to open the corresponding sound card and pcm device
when it wants to take the audio offload path.  This callback should return
the mapped indexes based on the USB SND device information.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409194804.3773260-18-quic_wcheng@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>