ASoC: Annotate core removal function

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 0448708..7eb2ea1f 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -1952,7 +1952,7 @@
 	return platform_driver_register(&soc_driver);
 }
 
-static void snd_soc_exit(void)
+static void __exit snd_soc_exit(void)
 {
 	platform_driver_unregister(&soc_driver);
 }