[BNX2]: Fix remote PHY media detection problems.

The remote PHY media type and link status can change between
->probe() and ->open().  For correct operation, we need to get the
new status again during ->open().

The ethtool link test and loopback test are also fixed to work with
remote PHY.  PHY loopback is simply skipped when remote PHY is
present.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>