ASoC: nau8825: remove useless assignment

cppcheck warning:

sound/soc/codecs/nau8825.c:2113:10: style: Variable 'ret' is assigned
a value that is never used. [unreadVariable]
 int ret = 0;
         ^

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210312182246.5153-16-pierre-louis.bossart@linux.intel.com


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