ip link: Add support to configure SR-IOV VF to vlan protocol 802.1ad (VST QinQ)

ip link: Add support to configure SR-IOV VF to vlan protocol 802.1ad (VST QinQ)

Introduce a new API that exposes a list of vlans per VF (IFLA_VF_VLAN_LIST),
giving the ability for user-space application to specify it for the VF as
an option to support 802.1ad (VST QinQ).

We introduce struct vf_vlan_info, which extends struct vf_vlan and adds
an optional VF VLAN proto parameter.
Default VLAN-protocol is 802.1Q.

Add IFLA_VF_VLAN_LIST in addition to IFLA_VF_VLAN to keep backward
compatibility with older kernel versions.

Suitable ip link tool command examples:
 - Set vf vlan protocol 802.1ad (S-TAG)
	ip link set eth0 vf 1 vlan 100 proto 802.1ad
 - Set vf vlan S-TAG and vlan C-TAG (VST QinQ)
	ip link set eth0 vf 1 vlan 100 proto 802.1ad vlan 30 proto 802.1Q
 - Set vf to VST (802.1Q) mode
	ip link set eth0 vf 1 vlan 100 proto 802.1Q
 - Or by omitting the new parameter (backward compatible)
	ip link set eth0 vf 1 vlan 100

Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>