ASoC: Add snd_soc_{add, remove}_platform

snd_soc_{add,remove}_platform are similar to snd_soc_register_platform and
snd_soc_unregister_platform with the difference that they won't allocate and
free the snd_soc_platform structure.

Also add snd_soc_lookup_platform which looks up a platform by the device it has
been registered for.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Stephen Warren <swarren@nvidia.com>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/include/sound/soc.h b/include/sound/soc.h
index f619905..4429254 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -373,6 +373,10 @@
 int snd_soc_register_platform(struct device *dev,
 		const struct snd_soc_platform_driver *platform_drv);
 void snd_soc_unregister_platform(struct device *dev);
+int snd_soc_add_platform(struct device *dev, struct snd_soc_platform *platform,
+		const struct snd_soc_platform_driver *platform_drv);
+void snd_soc_remove_platform(struct snd_soc_platform *platform);
+struct snd_soc_platform *snd_soc_lookup_platform(struct device *dev);
 int snd_soc_register_codec(struct device *dev,
 		const struct snd_soc_codec_driver *codec_drv,
 		struct snd_soc_dai_driver *dai_drv, int num_dai);