sctp: Fix use of uninitialized pointer

Introduced by c4492586 (sctp: Add address type check while process
paramaters of ASCONF chunk):

net/sctp/sm_make_chunk.c: In function 'sctp_process_asconf':
net/sctp/sm_make_chunk.c:2828: warning: 'addr_param' may be used uninitialized in this function
net/sctp/sm_make_chunk.c:2828: note: 'addr_param' was declared here
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Acked-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sctp/sm_make_chunk.c

@@ -2827,6 +2827,9 @@ static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
 	union sctp_addr	addr;
 	union sctp_addr_param *addr_param;
 
+	addr_param = (union sctp_addr_param *)
+			((void *)asconf_param + sizeof(sctp_addip_param_t));
+
 	switch (addr_param->v4.param_hdr.type) {
 	case SCTP_PARAM_IPV6_ADDRESS:
 		if (!asoc->peer.ipv6_address)
@@ -2840,9 +2843,6 @@ static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
 		return SCTP_ERROR_INV_PARAM;
 	}
 
-	addr_param = (union sctp_addr_param *)
-			((void *)asconf_param + sizeof(sctp_addip_param_t));
-
 	af = sctp_get_af_specific(param_type2af(addr_param->v4.param_hdr.type));
 	if (unlikely(!af))
 		return SCTP_ERROR_INV_PARAM;