bnx2x: Add 84858 phy support

This adds support to a new copper phy.

Signed-off-by: Yaniv Rosner <Yaniv.Rosner@qlogic.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>