ALSA: Deletion of checks before the function call "iounmap"

The iounmap() function performs also input parameter validation.
Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/cs4281.c b/sound/pci/cs4281.c
index 05a4337..ea33911 100644
--- a/sound/pci/cs4281.c
+++ b/sound/pci/cs4281.c
@@ -1316,10 +1316,8 @@
 
 	if (chip->irq >= 0)
 		free_irq(chip->irq, chip);
-	if (chip->ba0)
-		iounmap(chip->ba0);
-	if (chip->ba1)
-		iounmap(chip->ba1);
+	iounmap(chip->ba0);
+	iounmap(chip->ba1);
 	pci_release_regions(chip->pci);
 	pci_disable_device(chip->pci);