bridge: Fix setting a flag in br_fill_ifvlaninfo_range().

This patch fixes setting of vinfo.flags in the br_fill_ifvlaninfo_range() method. The
assignment of vinfo.flags &= ~BRIDGE_VLAN_INFO_RANGE_BEGIN has no effect and is
unneeded, as vinfo.flags value is overriden by the  immediately following
vinfo.flags = flags | BRIDGE_VLAN_INFO_RANGE_END assignement.

Signed-off-by: Rami Rosen <rami.rosen@intel.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>