ASoC: simple-card: Use snd_soc_of_parse_aux_devs()

Use the new common snd_soc_of_parse_aux_devs() helper function
to parse auxiliary devices from the device tree. The code is slightly
different but the binding that is parsed is exactly the same.

Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Link: https://lore.kernel.org/r/20200801100257.22658-2-stephan@gerhold.net


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