ASoC: core: Add devm_snd_soc_register_card()

Simplify error handling and remove repetitive (and rarely executed) code
for unregistration by providing a devm_snd_soc_register() card.

Signed-off-by: Mark Brown <broonie@linaro.org>
Acked-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
diff --git a/include/sound/soc.h b/include/sound/soc.h
index b970f01..d44728a 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -369,6 +369,7 @@
 
 int snd_soc_register_card(struct snd_soc_card *card);
 int snd_soc_unregister_card(struct snd_soc_card *card);
+int devm_snd_soc_register_card(struct device *dev, struct snd_soc_card *card);
 int snd_soc_suspend(struct device *dev);
 int snd_soc_resume(struct device *dev);
 int snd_soc_poweroff(struct device *dev);