qed: Add support for virtual link.

Currently driver registers to physical link notifications (of the device)
from Management firmware (MFW). Driver doesn't get notified if there's a
change in the virtual link e.g., link-flap on the peer PF interface.
Virtual link indication from MFW reflects the per PF link status instead
of the physical link.

The patch adds driver support for,
  - Advertising the virtual link support to MFW.
  - Handling the virtual link notification from MFW.

Please consider applying it to 'net-next'.

Signed-off-by: Sudarsana Reddy Kalluru <Sudarsana.Kalluru@cavium.com>
Signed-off-by: Tomer Tayar <Tomer.Tayar@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>