[BNX2]: New Broadcom gigabit network driver.

A new driver bnx2 for Broadcom bcm5706 is available.

The patch also includes new 1000BASE-X advertisement bit definitions in
mii.h

Thanks to David Miller and Jeff Garzik for reviewing and their valuable
feedback.

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