ASoC: samsung: Use snd_soc_substream_to_rtd() for accessing private_data

Do not open-code snd_soc_substream_to_rtd().
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240430-asoc-snd-substream-clean-v1-12-6f8a8902b479@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/samsung/midas_wm1811.c

@@ -127,7 +127,7 @@ static int midas_stop_fll1(struct snd_soc_pcm_runtime *rtd)
 static int midas_aif1_hw_params(struct snd_pcm_substream *substream,
 				struct snd_pcm_hw_params *params)
 {
-	struct snd_soc_pcm_runtime *rtd	= substream->private_data;
+	struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
 	unsigned int pll_out;
 
 	/* AIF1CLK should be at least 3MHz for "optimal performance" */