ASoC: amd: raven: acp3x-i2s: remove unused-but-set variable

Fix W=1 warning. The variable prtd is set but not used.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20200702164433.162815-7-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/amd/raven/acp3x-i2s.c

@@ -149,11 +149,9 @@ static int acp3x_i2s_trigger(struct snd_pcm_substream *substream,
 				int cmd, struct snd_soc_dai *dai)
 {
 	struct i2s_stream_instance *rtd;
-	struct snd_soc_pcm_runtime *prtd;
 	u32 ret, val, period_bytes, reg_val, ier_val, water_val;
 	u32 buf_size, buf_reg;
 
-	prtd = substream->private_data;
 	rtd = substream->runtime->private_data;
 	period_bytes = frames_to_bytes(substream->runtime,
 			substream->runtime->period_size);