ASoC: codecs: wcd938x: handle deferred probe

WCD938x sound codec driver ignores return status of getting regulators
and returns EINVAL instead of EPROBE_DEFER.  If regulator provider
probes after the codec, system is left without probed audio:

  wcd938x_codec audio-codec: wcd938x_probe: Fail to obtain platform data
  wcd938x_codec: probe of audio-codec failed with error -22

Fixes: 16572522

 ("ASoC: codecs: wcd938x-sdw: add SoundWire driver")
Cc:  <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://msgid.link/r/20240117151208.1219755-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>