bnx2x: convert to set_phys_id

Also cleanup error codes to no lie about things that driver doesn't
support. If device is down report -EAGAIN (same as Broadcom), and
if port doesn't blink then error as well.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>