ASoC: core - Add platform widget IO

Allow platform driver widgets to perform any IO required for DAPM.

Signed-off-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/include/sound/soc.h b/include/sound/soc.h
index c421501..6ce8dc3 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -682,6 +682,8 @@
 	struct snd_soc_card *card;
 	struct list_head list;
 	struct list_head card_list;
+
+	struct snd_soc_dapm_context dapm;
 };
 
 struct snd_soc_dai_link {