ethernet: make use of eth_hw_addr_random() where appropriate

Number of drivers use eth_random_addr(netdev->dev_addr)
thus writing to netdev->dev_addr directly, and not setting
the address type. Switch them to eth_hw_addr_random().

  @@
  expression netdev;
  @@
  - eth_random_addr(netdev->dev_addr);
  + eth_hw_addr_random(netdev);

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>