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>

dsp/codecs/amrwb_in.c

@@ -397,7 +397,7 @@ int __init amrwb_in_init(void)
 	return misc_register(&audio_amrwb_in_misc);
 }
 
-void __exit amrwb_in_exit(void)
+void amrwb_in_exit(void)
 {
 	misc_deregister(&audio_amrwb_in_misc);
 }