bnx2x: Add timestamping and PTP hardware clock support

This adds a PHC to the bnx2x driver. Driver supports timestamping send/receive
PTP packets, as well as adjusting the on-chip clock.

The driver has been tested with linuxptp project.

Signed-off-by: Michal Kalderon <Michal.Kalderon@qlogic.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: Ariel Elior <Ariel.Elior@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>