fm10k: use ether_addr_copy to copy MAC address

Cleanup the remaining instances of using memcpy() instead of the preferred
ether_addr_copy().

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>