ixgbe: Add DCB for 82599, remove BCN support

This patch adds the DCB (Data Center Bridging) support for 82599 hardware.
This is similar to how the 82598 DCB code works.

This patch also removes the BCN (Backwards Congestion Notification) netlink
configuration code from the driver.  BCN was a pre-standard congestion
notification framework, and was not what the IEEE body decided upon for
standard congestion management. QCN (802.1Qau), Quantized Congestion
Notification is the accepted standard, which is not supported by 82599,
hence we remove the support altogether.

Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>