firewire: don't write directly to netdev->dev_addr

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 go through appropriate helpers.

Prepare fwnet_hwaddr on the stack and use dev_addr_set() to copy
it to netdev->dev_addr. We no longer need to worry about alignment.
union fwnet_hwaddr does not have any padding and we set all fields
so we don't need to zero it upfront.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/firewire/net.c

@@ -1443,8 +1443,8 @@ static int fwnet_probe(struct fw_unit *unit,
 	struct net_device *net;
 	bool allocated_netdev = false;
 	struct fwnet_device *dev;
+	union fwnet_hwaddr ha;
 	int ret;
-	union fwnet_hwaddr *ha;
 
 	mutex_lock(&fwnet_device_mutex);
 
@@ -1491,12 +1491,12 @@ static int fwnet_probe(struct fw_unit *unit,
 	net->max_mtu = 4096U;
 
 	/* Set our hardware address while we're at it */
-	ha = (union fwnet_hwaddr *)net->dev_addr;
-	put_unaligned_be64(card->guid, &ha->uc.uniq_id);
-	ha->uc.max_rec = dev->card->max_receive;
-	ha->uc.sspd = dev->card->link_speed;
-	put_unaligned_be16(dev->local_fifo >> 32, &ha->uc.fifo_hi);
-	put_unaligned_be32(dev->local_fifo & 0xffffffff, &ha->uc.fifo_lo);
+	ha.uc.uniq_id = cpu_to_be64(card->guid);
+	ha.uc.max_rec = dev->card->max_receive;
+	ha.uc.sspd = dev->card->link_speed;
+	ha.uc.fifo_hi = cpu_to_be16(dev->local_fifo >> 32);
+	ha.uc.fifo_lo = cpu_to_be32(dev->local_fifo & 0xffffffff);
+	dev_addr_set(net, ha.u);
 
 	memset(net->broadcast, -1, net->addr_len);