ASoC: wm_adsp: Add missing MODULE_DESCRIPTION()

wm_adsp is built as a separate module and as such should include a
MODULE_DESCRIPTION() macro.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://msgid.link/r/20240527100237.430240-1-ckeepax@opensource.cirrus.com


Signed-off-by: Mark Brown <broonie@kernel.org>