netfilter: ipv6: use NFPROTO values for NF_HOOK invocation

The semantic patch that was used:
// <smpl>
@@
@@
(NF_HOOK
|NF_HOOK_THRESH
|nf_hook
)(
-PF_INET6,
+NFPROTO_IPV6,
 ...)
// </smpl>

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index dabf108..4535b7a 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -66,8 +66,8 @@
 		len = 0;
 	ipv6_hdr(skb)->payload_len = htons(len);
 
-	return nf_hook(PF_INET6, NF_INET_LOCAL_OUT, skb, NULL, skb_dst(skb)->dev,
-		       dst_output);
+	return nf_hook(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
+		       skb_dst(skb)->dev, dst_output);
 }
 
 int ip6_local_out(struct sk_buff *skb)
@@ -134,8 +134,8 @@
 			   is not supported in any case.
 			 */
 			if (newskb)
-				NF_HOOK(PF_INET6, NF_INET_POST_ROUTING, newskb,
-					NULL, newskb->dev,
+				NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING,
+					newskb, NULL, newskb->dev,
 					ip6_dev_loopback_xmit);
 
 			if (ipv6_hdr(skb)->hop_limit == 0) {
@@ -150,7 +150,7 @@
 				skb->len);
 	}
 
-	return NF_HOOK(PF_INET6, NF_INET_POST_ROUTING, skb, NULL, skb->dev,
+	return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL, skb->dev,
 		       ip6_output_finish);
 }
 
@@ -260,8 +260,8 @@
 	if ((skb->len <= mtu) || skb->local_df || skb_is_gso(skb)) {
 		IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
 			      IPSTATS_MIB_OUT, skb->len);
-		return NF_HOOK(PF_INET6, NF_INET_LOCAL_OUT, skb, NULL, dst->dev,
-				dst_output);
+		return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT, skb, NULL,
+			       dst->dev, dst_output);
 	}
 
 	if (net_ratelimit())
@@ -537,7 +537,7 @@
 	hdr->hop_limit--;
 
 	IP6_INC_STATS_BH(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTFORWDATAGRAMS);
-	return NF_HOOK(PF_INET6, NF_INET_FORWARD, skb, skb->dev, dst->dev,
+	return NF_HOOK(NFPROTO_IPV6, NF_INET_FORWARD, skb, skb->dev, dst->dev,
 		       ip6_forward_finish);
 
 error: