ASoC: dt-bindings: Add Q6USB backend

Add a dt-binding to describe the definition of enabling the Q6 USB backend
device for audio offloading.  The node carries information, which is passed
along to the QC USB SND class driver counterpart.  These parameters will be
utilized during QMI stream enable requests.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Link: https://lore.kernel.org/r/20240217001017.29969-36-quic_wcheng@quicinc.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>