i40e: Add init and default config of software based DCB

Add extra handling on changing the "disable-fw-lldp" private
flag to properly initialize software based DCB feature.

Add default configuration of DCB functionality when Firmware
LLDP agent is turned off, in case of driver probe and device
reset on reconfiguration.

Update copyright dates as appropriate.

Software based DCB is a brand-new feature in i40e driver.
Before, DCB was implemented by Firmware LLDP agent only. The agent was
responsible for handling incoming DCB-related LLDP frames and
applying received DCB configuration to hardware.

Default configuration and new initialization flow for software based
DCB is required. If LLDP agent is turned off in BIOS, or after
setting private flag ("disable-fw-lldp on"). The driver initializes
DCB functionality with default values, one traffic class with 100%
bandwidth allocated.

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>