ASoC: dapm: Fix locking during codec shutdown

Codec shutdown performs a DAPM power sequence that might cause conflicts
and/or race conditions if another stream power event is running simultaneously.
Use card's dapm mutex to protect any potential race condition between them.

Signed-off-by: Misael Lopez Cruz <misael.lopez@ti.com>
Signed-off-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@vger.kernel.org