ixgbe: remove unused fcoe.tc field and fcoe_setapp()

ixgbe: remove unused fcoe.tc field and fcoe_setapp()

The fcoe.tc field is no longer used so remove it. After
the field is removed there is no need to keep fcoe_setapp()
around so remove it as well. And finally we can get rid
of some DCB #ifdef's in the fcoe code.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from commit 3b3bf3b92b313db62a07869a649533f7f4f25c24)

Signed-off-by: Joe Jin <joe.jin@oracle.com>