ASoC: SOF: add missing MODULE_DESCRIPTION()

ASoC: SOF: add missing MODULE_DESCRIPTION()

MODULE_DESCRIPTION() was optional until it became mandatory and
flagged as an error by 'make W=1'.

Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://msgid.link/r/20240527194414.166156-5-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>