ALSA: seq: Fix init order of snd_seq_device stuff

When the sequencer driver is built in kernel, it may panic at boot
because of the uninitialized snd_seq_bus_type.  Initialize it properly
via subsys_initcall() instead of module_init() to assure that the bus
is registered beforehand.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Fixes: 7c37ae5c ('ALSA: seq: Rewrite sequencer device binding with standard bus')
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/core/seq/seq_device.c

@@ -311,5 +311,5 @@ static void __exit alsa_seq_device_exit(void)
 	bus_unregister(&snd_seq_bus_type);
 }
 
-module_init(alsa_seq_device_init)
+subsys_initcall(alsa_seq_device_init)
 module_exit(alsa_seq_device_exit)