ASoC: atmel: mchp-pdmc: set prepare_slave_config

ASoC: atmel: mchp-pdmc: set prepare_slave_config

Since a pointer to struct snd_dmaengine_pcm_config is passed,
snd_dmaengine_pcm_prepare_slave_config() is no longer called unless it's
explicitly set in prepare_slave_config.

Fixes: 50291652af52 ("ASoC: atmel: mchp-pdmc: add PDMC driver")
Suggested-by: Sascha Hauer <sha@pengutronix.de>
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Link: https://lore.kernel.org/r/20220421125403.2180824-2-codrin.ciubotariu@microchip.com
Signed-off-by: Mark Brown <broonie@kernel.org>