netfilter: nf_nat: add missing nla_policy entry for CTA_NAT_PROTO attribute

Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

net/ipv4/netfilter/nf_nat_core.c

@@ -622,6 +622,7 @@ static int nfnetlink_parse_nat_proto(struct nlattr *attr,
 static const struct nla_policy nat_nla_policy[CTA_NAT_MAX+1] = {
 	[CTA_NAT_MINIP]		= { .type = NLA_U32 },
 	[CTA_NAT_MAXIP]		= { .type = NLA_U32 },
+	[CTA_NAT_PROTO]		= { .type = NLA_NESTED },
 };
 
 static int