ASoC: fix kernel-doc warnings in sound/soc/soc-ops.c

Fix kernel-doc warnings in soc-ops.c:

..//sound/soc/soc-ops.c:415: warning: No description found for parameter 'ucontrol'
..//sound/soc/soc-ops.c:415: warning: Excess function parameter 'uinfo' description in 'snd_soc_put_volsw_sx'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc:	Liam Girdwood <lgirdwood@gmail.com>
Cc:	Mark Brown <broonie@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>