[ALSA] Fix missing spin_unlock

au88x0 driver,Common EMU synth
Fixed missing spin_unlock.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/au88x0/au88x0_pcm.c b/sound/pci/au88x0/au88x0_pcm.c
index de95bd6..38bd2b5d 100644
--- a/sound/pci/au88x0/au88x0_pcm.c
+++ b/sound/pci/au88x0/au88x0_pcm.c
@@ -220,8 +220,10 @@
 		    vortex_adb_allocroute(chip, -1,
 					  params_channels(hw_params),
 					  substream->stream, type);
-		if (dma < 0)
+		if (dma < 0) {
+			spin_unlock_irq(&chip->lock);
 			return dma;
+		}
 		stream = substream->runtime->private_data = &chip->dma_adb[dma];
 		stream->substream = substream;
 		/* Setup Buffers. */