be2net: Add functionality to support RoCE driver

- Increase MSI-X vectors by 5 for RoCE traffic.
- Add macro to check roce support on a device.
- Add device-specific doorbell and MSI-X vector fields shared with NIC
  functionality.
- Provide RoCE driver registration and deregistration functions.
- Add support functions which will be invoked on adapter add/remove
  and port up/down events.
- Traverse through the list of adapters to invoke callback functions.

Signed-off-by: Parav Pandit <parav.pandit@emulex.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Roland Dreier <roland@purestorage.com>