An earlier commit removed the access to variable runtime
and we are now left with unused variable that is redundant,
so remove it.

Cleans up the clang warning: Value stored to 'runtime' is never read

Fixes: e11f0f90 ("ALSA: pcm: remove SNDRV_PCM_IOCTL1_INFO internal command")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>