media: 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 go through appropriate helpers.

Convert media from memcpy(... 6) and memcpy(... addr_len) to
eth_hw_addr_set():

  @@
  expression dev, np;
  @@
  - memcpy(dev->dev_addr, np, 6)
  + eth_hw_addr_set(dev, np)
  @@
  - memcpy(dev->dev_addr, np, dev->addr_len)
  + eth_hw_addr_set(dev, np)

Make sure we don't cast off const qualifier from dev->dev_addr.

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