ASoC: rt5682: remove useless initialization

cppcheck complains about a possible null pointer dereference, but the
problem is rather an useless initialization before walking through a
list.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210302212527.55158-25-pierre-louis.bossart@linux.intel.com


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