if_link: Add control trust VF

Add netlink directives and ndo entry to trust VF user.

This controls the special permission of VF user.
The administrator will dedicatedly trust VF user to use some features
which impacts security and/or performance.

The administrator never turn it on unless VF user is fully trusted.

CC: Sy Jong Choi <sy.jong.choi@intel.com>
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Acked-by: Greg Rose <gregory.v.rose@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>