ALSA: ASoC: add DT bindings for CS4271

Apart from pure matching, the bindings also support setting the the
reset gpio line.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Cc: Alexander Sverdlin <subaparts@yandex.ru>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>