[ALSA] Fix synchronize_irq() bugs, redundancies

free_irq() calls synchronize_irq() for you, so there is no need for
drivers to manually do the same thing (again).  Thus, calls where
sync-irq immediately precedes free-irq can be simplified.

However, during this audit several bugs were noticed, where free-irq is
preceded by a "irq >= 0" check... but the sync-irq call is not covered
by the same check.

So, where sync-irq could not be eliminated completely, the missing check
was added.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/drivers/media/video/saa7134/saa7134-alsa.c b/drivers/media/video/saa7134/saa7134-alsa.c
index 047add8..ec6bdb9 100644
--- a/drivers/media/video/saa7134/saa7134-alsa.c
+++ b/drivers/media/video/saa7134/saa7134-alsa.c
@@ -954,10 +954,8 @@
 	if (chip->dev->dmasound.priv_data == NULL)
 		return;
 
-	if (chip->irq >= 0) {
-		synchronize_irq(chip->irq);
+	if (chip->irq >= 0)
 		free_irq(chip->irq, &chip->dev->dmasound);
-	}
 
 	chip->dev->dmasound.priv_data = NULL;