dcbnl: Aggregated CEE GET operation

The following couple of patches add dcbnl an unsolicited notification of
the the DCB configuration for the CEE flavor of the DCBX protocol. This
is useful when the user-mode DCB client is not responsible for
conducting and resolving the DCBX negotiation (either because the DCBX
stack is embedded in the HW or the negotiation is handled by another
agent in the host), but still needs to get the negotiated parameters.
This functionality already exists for the IEEE flavor of the DCBX
protocol and these patches add it to the older CEE flavor.

The first patch extends the CEE attribute GET operation to include not
only the peer information, but also all the pertinent local
configuration (negotiated parameters). The second patch adds and export
a CEE specific notification routine.

Signed-off-by: Shmulik Ravid <shmulikr@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>