ASoC: ssm2518: switch to using gpiod API

This patch converts the driver to newer gpiod API, so that we can stop
exporting OF-specific legacy gpio API.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Link: https://lore.kernel.org/r/20220920025804.1788667-2-dmitry.torokhov@gmail.com


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