ALSA: echoaudio: Prevent races in calls to set_audio_format()

The function uses chip->comm_page which needs locking against
other use at the same time.

Signed-off-by: Mark Hills <mark@xwax.org>
Link: https://lore.kernel.org/r/20200708101848.3457-3-mark@xwax.org


Signed-off-by: Takashi Iwai <tiwai@suse.de>