ixgbe: dcb: BIT_APP_UPCHG not set by ixgbe_copy_dcb_cfg()

After this commit:

commit aacc1bea190d731755a65cb8ec31dd756f4e263e
Author: Multanen, Eric W <eric.w.multanen@intel.com>
Date:   Wed Mar 28 07:49:09 2012 +0000

    ixgbe: driver fix for link flap

The BIT_APP_UPCHG bit is no longer set when ixgbe_dcbnl_set_all() is
called. This results in the FCoE app user priority never getting set
and the driver will not configure the tx_rings correctly for FCoE
packets which use the SAN MTU and FCoE offloads.

We resolve this regression by fixing ixgbe_copy_dcb_cfg() to also
check for FCoE application changes. Additionally, we can drop the
IEEE variants of get_dcb_app() because this path is never called
with the IEEE mode enabled.

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>