ipv6: Use ipv6_get_dsfield() instead of ipv6_tclass().

Commit 7a3198a8 ("ipv6: helper function to get tclass") introduced
ipv6_tclass(), but similar function is already available as
ipv6_get_dsfield().

We might be able to call ipv6_tclass() from ipv6_get_dsfield(),
but it is confusing to have two versions.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 3164ad2..3701c3c 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1163,7 +1163,7 @@
 		newnp->opt	   = NULL;
 		newnp->mcast_oif   = inet6_iif(skb);
 		newnp->mcast_hops  = ipv6_hdr(skb)->hop_limit;
-		newnp->rcv_tclass  = ipv6_tclass(ipv6_hdr(skb));
+		newnp->rcv_tclass  = ipv6_get_dsfield(ipv6_hdr(skb));
 
 		/*
 		 * No need to charge this sock to the relevant IPv6 refcnt debug socks count
@@ -1243,7 +1243,7 @@
 	newnp->opt	  = NULL;
 	newnp->mcast_oif  = inet6_iif(skb);
 	newnp->mcast_hops = ipv6_hdr(skb)->hop_limit;
-	newnp->rcv_tclass = ipv6_tclass(ipv6_hdr(skb));
+	newnp->rcv_tclass = ipv6_get_dsfield(ipv6_hdr(skb));
 
 	/* Clone native IPv6 options from listening socket (if any)
 
@@ -1456,7 +1456,7 @@
 		if (np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim)
 			np->mcast_hops = ipv6_hdr(opt_skb)->hop_limit;
 		if (np->rxopt.bits.rxtclass)
-			np->rcv_tclass = ipv6_tclass(ipv6_hdr(skb));
+			np->rcv_tclass = ipv6_get_dsfield(ipv6_hdr(skb));
 		if (ipv6_opt_accepted(sk, opt_skb)) {
 			skb_set_owner_r(opt_skb, sk);
 			opt_skb = xchg(&np->pktoptions, opt_skb);