ALSA: sh: Fix unused variable warnings

Remove unused variables that are left over after the conversion of new
PCM ops:
  sound/sh/sh_dac_audio.c:166:26: warning: unused variable 'runtime'
  sound/sh/sh_dac_audio.c:186:26: warning: unused variable 'runtime'
  sound/sh/sh_dac_audio.c:205:26: warning: unused variable 'runtime'

Fixes: 1cc2f8ba ("ALSA: sh: Convert to the new PCM ops")
Link: https://lore.kernel.org/r/20200104110057.13875-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/sh/sh_dac_audio.c

@@ -163,7 +163,6 @@ static int snd_sh_dac_pcm_copy(struct snd_pcm_substream *substream,
 {
 	/* channel is not used (interleaved data) */
 	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
-	struct snd_pcm_runtime *runtime = substream->runtime;
 
 	if (copy_from_user_toio(chip->data_buffer + pos, src, count))
 		return -EFAULT;
@@ -183,7 +182,6 @@ static int snd_sh_dac_pcm_copy_kernel(struct snd_pcm_substream *substream,
 {
 	/* channel is not used (interleaved data) */
 	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
-	struct snd_pcm_runtime *runtime = substream->runtime;
 
 	memcpy_toio(chip->data_buffer + pos, src, count);
 	chip->buffer_end = chip->data_buffer + pos + count;
@@ -202,7 +200,6 @@ static int snd_sh_dac_pcm_silence(struct snd_pcm_substream *substream,
 {
 	/* channel is not used (interleaved data) */
 	struct snd_sh_dac *chip = snd_pcm_substream_chip(substream);
-	struct snd_pcm_runtime *runtime = substream->runtime;
 
 	memset_io(chip->data_buffer + pos, 0, count);
 	chip->buffer_end = chip->data_buffer + pos + count;