commit e6355ad7 upstream.

snd_pcm_stop() must be called in the PCM substream lock context.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
[wml: Backported to 3.4: Adjust filename]
Signed-off-by: Weng Meiling <wengmeiling.weng@huawei.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>