libnetlink: linkdump_req: AF_PACKET family also expects ext_filter_mask

libnetlink: linkdump_req: AF_PACKET family also expects ext_filter_mask

Without this fix, the VF info can't be showed using command
"ip link".

146: ens1f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP mode DEFAULT group default qlen 1000
    link/ether 24:8a:07:ad:78:52 brd ff:ff:ff:ff:ff:ff
    vf 0 MAC 02:25:d0:12:01:01, spoof checking off, link-state auto, trust off, query_rss off
    vf 1 MAC 02:25:d0:12:01:02, spoof checking off, link-state auto, trust off, query_rss off

Fixes: d97b16b2c906 ("libnetlink: linkdump_req: Only AF_UNSPEC family expects an ext_filter_mask")
Signed-off-by: Chris Mi <chrism@mellanox.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>