ASoC: s6000: Fix unlocked snd_pcm_stop() call

commit 61be2b9a18ec70f3cbe3deef7a5f77869c71b5ae upstream.

snd_pcm_stop() must be called in the PCM substream lock context.

Acked-by: Mark Brown <broonie@linaro.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>