ASoC: dapm: Move snd_soc_dapm_update from dapm context to card

The update field of a DAPM context is only assigned while the card's dapm_mutex
is locked, the field is also cleared again while the mutex is stil locked. So
there will only ever be one DAPM context at a time with a non-NULL update field.
So it is safe to move the update field from the DAPM context struct to the card
struct. Doing so will allow further cleanups in this area.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/include/sound/soc.h b/include/sound/soc.h
index 6eabee7..b1e1f96 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -1042,6 +1042,7 @@
 	/* Generic DAPM context for the card */
 	struct snd_soc_dapm_context dapm;
 	struct snd_soc_dapm_stats dapm_stats;
+	struct snd_soc_dapm_update *update;
 
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *debugfs_card_root;