i40e: Do not allow untrusted VF to remove administratively set MAC

In the Linux kernel, the following vulnerability has been resolved: i40e: Do not allow untrusted VF to remove administratively set MAC Currently when PF administratively sets VF's MAC address and the VF is put down (VF tries to delete all MACs) then the MAC is removed from MAC filters and primary VF MAC is zeroed. Do not allow untrusted VF to remove primary MAC when it was set administratively by PF. Reproducer: 1) Create VF 2) Set VF interface up 3) Administratively set the VF's MAC 4) Put VF interface down [root@host ~]# echo 1 > /sys/class/net/enp2s0f0/device/sriov_numvfs [root@host ~]# ip link set enp2s0f0v0 up [root@host ~]# ip link set enp2s0f0 vf 0 mac fe:6c:b5:da:c7:7d [root@host ~]# ip link show enp2s0f0 23: enp2s0f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000 link/ether 3c:ec:ef:b7:dd:04 brd ff:ff:ff:ff:ff:ff vf 0 link/ether fe:6c:b5:da:c7:7d brd ff:ff:ff:ff:ff:ff, spoof checking on, link-state auto, trust off [root@host ~]# ip link set enp2s0f0v0 down [root@host ~]# ip link show enp2s0f0 23: enp2s0f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000 link/ether 3c:ec:ef:b7:dd:04 brd ff:ff:ff:ff:ff:ff vf 0 link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff, spoof checking on, link-state auto, trust off