i40e: Correct UDP packet header for non_tunnel-ipv6

This patch corrects Rx ptype payload layer for non_tunneled ipv6. It
should be layer 4 for UDP, instead of layer 3.

Change-ID: I9382e4458ab3c4e58f6d2e9f195d5d4ee513805e
Signed-off-by: Akeem G Abodunrin <akeem.g.abodunrin@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>