qede: Add dcbnl support.

This patch adds the interfaces for ieee/cee dcbnl callbacks and registers
them with the kernel.

Signed-off-by: Sudarsana Reddy Kalluru <sudarsana.kalluru@qlogic.com>
Signed-off-by: Yuval Mintz <Yuval.Mintz@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>