sctp: Do not enable peer IPv6 address support on PF_INET socket

If socket is create by PF_INET type, it can not used IPv6 address to
send/recv DATA, So we can not used IPv6 address even if peer tell us it
support IPv6 address.
This patch fix to only enabled peer IPv6 address support on PF_INET6 socket.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index 81b6064..69a464f 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -2418,7 +2418,8 @@
 				break;
 
 			case SCTP_PARAM_IPV6_ADDRESS:
-				asoc->peer.ipv6_address = 1;
+				if (PF_INET6 == asoc->base.sk->sk_family)
+					asoc->peer.ipv6_address = 1;
 				break;
 
 			case SCTP_PARAM_HOST_NAME_ADDRESS: