ALSA: drivers: Remove empty init and exit

For a sake of code simplification, remove the init and the exit
entries that do nothing.

Notes for readers: actually it's OK to remove *both* init and exit,
but not OK to remove the exit entry.  By removing only the exit while
keeping init, the module becomes permanently loaded; i.e. you cannot
unload it any longer!

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/drivers/opl3/opl3_lib.c

@@ -538,19 +538,3 @@ int snd_opl3_hwdep_new(struct snd_opl3 * opl3,
 }
 
 EXPORT_SYMBOL(snd_opl3_hwdep_new);
-
-/*
- *  INIT part
- */
-
-static int __init alsa_opl3_init(void)
-{
-	return 0;
-}
-
-static void __exit alsa_opl3_exit(void)
-{
-}
-
-module_init(alsa_opl3_init)
-module_exit(alsa_opl3_exit)