airo: 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.

Use dev_addr_set() to match the existing logic.
setup_card() is always passed netdev->dev_addr, so pass the netdev
pointer instead and assign the address using a helper there.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211018235021.1279697-9-kuba@kernel.org