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 <[e-mail]>

sound/drivers/mpu401/mpu401_uart.c

···
 }
 
 EXPORT_SYMBOL(snd_mpu401_uart_new);
-
-/*
- *  INIT part
- */
-
-static int __init alsa_mpu401_uart_init(void)
-{
-	return 0;
-}
-
-static void __exit alsa_mpu401_uart_exit(void)
-{
-}
-
-module_init(alsa_mpu401_uart_init)
-module_exit(alsa_mpu401_uart_exit)

sound/drivers/opl3/opl3_lib.c

···
 }
 
 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)

sound/drivers/opl4/opl4_lib.c

···
 }
 
 EXPORT_SYMBOL(snd_opl4_create);
-
-static int __init alsa_opl4_init(void)
-{
-	return 0;
-}
-
-static void __exit alsa_opl4_exit(void)
-{
-}
-
-module_init(alsa_opl4_init)
-module_exit(alsa_opl4_exit)

sound/drivers/vx/vx_core.c

···
 }
 
 EXPORT_SYMBOL(snd_vx_create);
-
-/*
- * module entries
- */
-static int __init alsa_vx_core_init(void)
-{
-	return 0;
-}
-
-static void __exit alsa_vx_core_exit(void)
-{
-}
-
-module_init(alsa_vx_core_init)
-module_exit(alsa_vx_core_exit)