ALSA: fireworks/firewire-lib: Add a quirk for empty packet with TAG0

Fireworks has a quirk to transmit empty packets with TAG0. This commit
adds handling this quirk for full duplex stream synchronization.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/firewire/amdtp.h b/sound/firewire/amdtp.h
index 3de34639..96b96ec 100644
--- a/sound/firewire/amdtp.h
+++ b/sound/firewire/amdtp.h
@@ -18,11 +18,13 @@
  *	the overall sample rate comes out right.
  * @CIP_SYNC_TO_DEVICE: In sync to device mode, time stamp in out packets is
  *	generated by in packets. Defaultly this driver generates timestamp.
+ * @CIP_EMPTY_WITH_TAG0: Only for in-stream. Empty in-packets have TAG0.
  */
 enum cip_flags {
 	CIP_NONBLOCKING		= 0x00,
 	CIP_BLOCKING		= 0x01,
 	CIP_SYNC_TO_DEVICE	= 0x02,
+	CIP_EMPTY_WITH_TAG0	= 0x04,
 };
 
 /**