wl1271: add missing spin_lock()

We should start the loop consistently with the "wl_lock" lock held.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/wl12xx/wl1271_main.c

@@ -466,6 +466,7 @@ static void wl1271_irq_work(struct work_struct *work)
 		intr = le32_to_cpu(wl->fw_status->intr);
 		if (!intr) {
 			wl1271_debug(DEBUG_IRQ, "Zero interrupt received.");
+			spin_lock_irqsave(&wl->wl_lock, flags);
 			continue;
 		}