With the VLAN filtering feature, the Linux bridge acts more like a
real switch. Administrators can control all VLANs with only one
bridge, making it more easy and efficient to set up distinct subnets
on virtualization servers.

Kubernetes cni (container network interface) takes advantages of this
feature to configure pod network.

There will be error prompt like below if BRIDGE_VLAN_FILTERING is not
set.
NetworkPlugin cni failed to set up pod "<pod-name>" network: failed to
create bridge "cni0": could not add "cni0": operation not supported.

Therefore, enable BRIDGE_VLAN_FILTERING in this commit.
Signed-off-by: NXu Yu <xuyu@linux.alibaba.com>
Acked-by: NJoseph Qi <joseph.qi@linux.alibaba.com>