pciehp: removes redundant NULL write to slot status register

Cleanup to remove a redundant NULL write to SLOTSTATUS.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

drivers/pci/hotplug/pciehp_hpc.c

@@ -777,7 +777,7 @@ static irqreturn_t pcie_isr(int irq, void *dev_id)
 		intr_loc |= detected;
 		if (!intr_loc)
 			return IRQ_NONE;
-		if (pciehp_writew(ctrl, SLOTSTATUS, detected)) {
+		if (detected && pciehp_writew(ctrl, SLOTSTATUS, detected)) {
 			err("%s: Cannot write to SLOTSTATUS\n", __func__);
 			return IRQ_NONE;
 		}