staging: wfx: fix setting MAC address from DT

MAC address read from chip is unconditionally used even if a MAC
address is configured in device tree.
Reported-by: Marc Dorval <marc.dorval@silabs.com>
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20191017093954.657-5-Jerome.Pouiller@silabs.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wfx/main.c

@@ -410,8 +410,9 @@ int wfx_probe(struct wfx_dev *wdev)
 		if (!IS_ERR_OR_NULL(macaddr)) {
 			ether_addr_copy(wdev->addresses[i].addr, macaddr);
 			wdev->addresses[i].addr[ETH_ALEN - 1] += i;
+		} else {
+			ether_addr_copy(wdev->addresses[i].addr, wdev->hw_caps.mac_addr[i]);
 		}
-		ether_addr_copy(wdev->addresses[i].addr, wdev->hw_caps.mac_addr[i]);
 		if (!is_valid_ether_addr(wdev->addresses[i].addr)) {
 			dev_warn(wdev->dev, "using random MAC address\n");
 			eth_random_addr(wdev->addresses[i].addr);