ASoC: Remove unused soc_pm_waitq

The soc_pm_waitq waitqueue has been around as long as the ASoC framework
existed, but has never been used so far, so remove it.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/soc-core.c

@@ -47,8 +47,6 @@
 
 #define NAME_SIZE	32
 
-static DECLARE_WAIT_QUEUE_HEAD(soc_pm_waitq);
-
 #ifdef CONFIG_DEBUG_FS
 struct dentry *snd_soc_debugfs_root;
 EXPORT_SYMBOL_GPL(snd_soc_debugfs_root);