rename dev_hw_addr_random and remove redundant second

Renamed dev_hw_addr_random to eth_hw_addr_random() to reflect that
this function only assign a random ethernet address (MAC). Removed
the second parameter (u8 *hwaddr), it's redundant since the also
given net_device already contains net_device->dev_addr.
Set it directly.

Adapt igbvf and ixgbevf to the changed function.

Small fix for ixgbevf_probe(): if ixgbevf_sw_init() fails
(which means the device got no dev_addr) handle the error and
jump to err_sw_init as already done by igbvf in similar case.

Signed-off-by: Danny Kukawka <danny.kukawka@bisect.de>
Signed-off-by: David S. Miller <davem@davemloft.net>