ASoC: allow drivers to compile both static and dynamic

Based on where the code is synced the driver should allow
both static and dynamic linked compilation.
Also remove __exit for modules loaded from another common
init/exit functions.

Change-Id: Ib58f152002aba3af4446f9bbd9b82c279212bd0a
Signed-off-by: Asish Bhattacharya <asishb@codeaurora.org>

asoc/msm-pcm-dtmf-v2.c

@@ -585,7 +585,7 @@ int __init msm_pcm_dtmf_init(void)
 	return platform_driver_register(&msm_pcm_driver);
 }
 
-void __exit msm_pcm_dtmf_exit(void)
+void msm_pcm_dtmf_exit(void)
 {
 	platform_driver_unregister(&msm_pcm_driver);
 }