ASoC: core: Replace soc_find_matching_codec() with soc_find_codec()

soc_find_matching_codec() works in the same way as soc_find_codec() except that
it only works for auxdevs. It can easily be replaced by the generic
soc_find_codec().

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>