i40e: Add missing parameter comment to ndo_bridge_setlink

Add nlflags to the function comment for ndo_bridge_setlink.

Change-ID: I34c704f307f2a3f7bac3ca4b44e2a094d3d082d6
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>