ASoC: cs42l52: Minor tidy up of error paths

Fixup a needlessly initialised variable and an unchecked return
value.

Reported-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20210511101051.17726-3-ckeepax@opensource.cirrus.com


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