soundwire: mipi-disco: remove DPn audio-modes

The concept of DPn audio-modes was never used by anyone, and was
removed from the DisCo for SoundWire 2.0 specification.

Remove the definitions and TODO.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20241003070650.62787-9-yung-chuan.liao@linux.intel.com


Signed-off-by: Vinod Koul <vkoul@kernel.org>