i40e: Add netlink callbacks support for software based DCB

Add callbacks used by software based LLDP agent, which allows to
configure DCB feature from userspace.

Update copyright dates as appropriate.

If LLDP agent is turned off in BIOS, or after setting private flag
("disable-fw-lldp on"). The driver initialized DCB functionality with
default values, one traffic class with 100% bandwidth allocated.

The new netlink callbacks are required for software LLDP agent, it
must be able to acquire current DCB configuration of a network port
and apply DCB configuration changes, if required.

Signed-off-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Signed-off-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Tested-by: Tony Brelinski <tonyx.brelinski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>