[PATCH] sb1250-mac: PHY probing fixes.

Improve sb1250-mac driver to probe for PHYs at addresses other
than 1, such as the PHYs on BigSur.

Signed-Off-By: Andy Isaacson <adi@broadcom.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>