i40e: remove FD atr control from debugfs

Since the flow-director-atr priv flag was added to our ethtool interface,
we don't need the on/off control in debugfs.

Change-ID: Ib3b599916434ab30ccd40074e71d7a81609b5bb5
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>