Use DCB notifiers to set the skb priority to allow packets
to be steered and tagged correctly over DCB enabled drivers
that setup traffic classes.

This allows queue_mapping() routines to be removed in these
drivers that were previously inspecting the ethertype of
every skb to mark FCoE/FIP frames.
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>