i40e: complain about out-of-range descriptor request

Instead of silently clamping the descriptor change request into
the proper range, fail the request and complain in the log file.

Change-Id: Id55ef59255d93c04bedffa8e25fe7ea796c90f32
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Kavindya Deegala <kavindya.s.deegala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --cc drivers/net/ethernet/intel/i40e/i40e_ethtool.c
Simple merge