ASoC: rt5631: fix kernel-doc warning

make W=1 warning:

sound/soc/codecs/rt5631.c:446: warning: expecting prototype for
onebit_depop_power_stage(). Prototype was for depop_seq_power_stage()
instead

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210302205926.49063-4-pierre-louis.bossart@linux.intel.com


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