ethernet: ixgb: use eth_hw_addr_set()

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.

Read the address into an array on the stack, then call
eth_hw_addr_set(). ixgb_get_ee_mac_addr() is used with
a non-nevdev->dev_addr pointer so we can't deal with the problem
inside it.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>