ASoC: sam9g20_wm8731: Use dev_err_probe() for snd_soc_register_card()

Log the error code when snd_soc_regster_card() fails, but fold in the
silencing of deferred probe errors.

Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Link: https://lore.kernel.org/r/20220506130349.451452-1-broonie@kernel.org