bridge: fix uninitialized variable warning

net/bridge/br_netlink.c: In function ‘br_fill_ifinfo’:
net/bridge/br_netlink.c:146:32: warning: ‘vid_range_flags’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  err = br_fill_ifvlaninfo_range(skb, vid_range_start,
                                ^
net/bridge/br_netlink.c:108:6: note: ‘vid_range_flags’ was declared here
  u16 vid_range_flags;

Reported-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>