teamd: lw: arp_ping: bitmask VID in VLAN BPF filter

BPF filter arp_vlan_rpl_flt fails if in the ARP response the VLAN tag has,
in addition to VID, also PCP (priority code point).
This patch is masking the last 12 bits from SKF_AD_VLAN_TAG field
to extract VID only.

Signed-off-by: Robert Karbowski <robert_karbowski@hotmail.com>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>