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: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sctp/sm_make_chunk.c

@@ -2418,7 +2418,8 @@ static int sctp_process_param(struct sctp_association *asoc,
 				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: