[NETFILTER]: IPv6 capable xt_tos v1 match

Extends the xt_dscp match by xt_tos v1 to add support for selectively
matching any bit in the IPv4 TOS and IPv6 Priority fields. (ipt_tos
and xt_dscp only accepted a limited range of possible values.)

Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>