ixgbe: DCB, remove RESET bit it is no longer needed

This removes the RESET bit previously used to force a device
reset when DCB bandwidth configurations were changed. This can
now be done dynamically without a reset so the bit is no longer
needed. The only remaining operations that force a device reset
are DCB enable/disable and FCoE application priority changes.
DCB enable/disable is a hardware requirement.

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>