ALSA: seq: Drop snd_seq_autoload_lock() and _unlock()

The autoload lock became already superfluous due to the recent rework
of autoload code.  Let's drop them now.  This allows us to simplify a
few codes nicely.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/seq/seq_midi.c b/sound/core/seq/seq_midi.c
index 79c7311..5dd0ee2 100644
--- a/sound/core/seq/seq_midi.c
+++ b/sound/core/seq/seq_midi.c
@@ -469,20 +469,4 @@
 	.argsize = 0,
 };
 
-static int __init alsa_seq_midi_init(void)
-{
-	int err;
-
-	snd_seq_autoload_lock();
-	err = snd_seq_driver_register(&seq_midisynth_driver);
-	snd_seq_autoload_unlock();
-	return err;
-}
-
-static void __exit alsa_seq_midi_exit(void)
-{
-	snd_seq_driver_unregister(&seq_midisynth_driver);
-}
-
-module_init(alsa_seq_midi_init)
-module_exit(alsa_seq_midi_exit)
+module_snd_seq_driver(seq_midisynth_driver);