i40e: fix incorrect ethtool statistics veb and veb.tc_

This patch fixes missing call of i40e_update_veb_stats() in function
i40e_get_ethtool_stats() to update stats data of VEB and VEB TC
counters before they are written into ethtool buffer.
Before the patch ethtool counters may fell behind interface counters.

Signed-off-by: Dmitrii Golovanov <dmitrii.golovanov@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>