ALSA: firewire-lib: add new function to schedule a work for sound card registration

In former commit, ALSA dice driver postpone sound card registration after
IEEE 1394 bus is calm. This idea has advantages for the other drivers.

This commit adds a helper function for it to firewire-lib module. The
function is really for the specific purpose. Callers should initialize
delayed work structure with callback function.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/firewire/lib.h b/sound/firewire/lib.h
index f3f6f84..f676931 100644
--- a/sound/firewire/lib.h
+++ b/sound/firewire/lib.h
@@ -22,6 +22,9 @@
 	return rcode == RCODE_TYPE_ERROR || rcode == RCODE_ADDRESS_ERROR;
 }
 
+void snd_fw_schedule_registration(struct fw_unit *unit,
+				  struct delayed_work *dwork);
+
 struct snd_fw_async_midi_port;
 typedef int (*snd_fw_async_midi_port_fill)(
 				struct snd_rawmidi_substream *substream,