i40e/i40evf: properly report Rx packet hash

This logic is inverted. If the RXHASH flag is set, then we should go
ahead and call skb_set_hash.

Change-ID: Ib2e30356dced1d3e939c8061ab6ad5bd94197e7c
Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>