Implements the new netdev op to trust VF in ixgbe.

The administrator can turn on and off VF trusted by ip command which
supports trust message.
 # ip link set dev eth0 vf 1 trust on
or
 # ip link set dev eth0 vf 1 trust off

Send a ping to reset VF on changing the status of trusting.
VF driver will reconfigure its features on reset.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>