wireless, at76c50x:: Don't needlessly test for NULL before calling release_firmware()

The release_firmware() function deals gracefully with being passed a
NULL pointer, so explicit tests before the call are rather pointless.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/at76c50x-usb.c

@@ -2512,10 +2512,8 @@ static void __exit at76_mod_exit(void)
 
 	printk(KERN_INFO DRIVER_DESC " " DRIVER_VERSION " unloading\n");
 	usb_deregister(&at76_driver);
-	for (i = 0; i < ARRAY_SIZE(firmwares); i++) {
-		if (firmwares[i].fw)
-			release_firmware(firmwares[i].fw);
-	}
+	for (i = 0; i < ARRAY_SIZE(firmwares); i++)
+		release_firmware(firmwares[i].fw);
 	led_trigger_unregister_simple(ledtrig_tx);
 }