i40e/i40evf: prefetch skb data on transmit

i40e/i40evf: prefetch skb data on transmit

Orabug: 22342532

Issue a prefetch for data early in the transmit path.
This should not be generally needed for Tx traffic, but
it helps immensely for pktgen workloads and should help
for forwarding workloads as well.

Change-ID: Iefee870c20599e0c4240e1d8637e4f16b625f83a
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from commit b74118f08356fd8ab6cb5d1a15705a2760c9afdd)
Signed-off-by: Brian Maly <brian.maly@oracle.com>