net: qmi_wwan: use dev_addr_mod()

Commit 406f42fa ("net-next: When a bond have a massive amount
of VLANs...") introduced a rbtree for faster Ethernet address look
up. To maintain netdev->dev_addr in this tree we need to make all
the writes to it got through appropriate helpers.
Acked-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/usb/qmi_wwan.c

@@ -835,8 +835,11 @@ static int qmi_wwan_bind(struct usbnet *dev, struct usb_interface *intf)
 
 	/* make MAC addr easily distinguishable from an IP header */
 	if (possibly_iphdr(dev->net->dev_addr)) {
-		dev->net->dev_addr[0] |= 0x02;	/* set local assignment bit */
-		dev->net->dev_addr[0] &= 0xbf;	/* clear "IP" bit */
+		u8 addr = dev->net->dev_addr[0];
+
+		addr |= 0x02;	/* set local assignment bit */
+		addr &= 0xbf;	/* clear "IP" bit */
+		dev_addr_mod(dev->net, 0, &addr, 1);
 	}
 	dev->net->netdev_ops = &qmi_wwan_netdev_ops;
 	dev->net->sysfs_groups[0] = &qmi_wwan_sysfs_attr_group;