sctp: use common head of addr parameter to access member in addr-unrelated code

The 'p' member of struct sctp_paramhdr is common part for
IPv4 addr parameter and IPv6 addr parameter in union sctp_addr_param.

For addr-related code, use specified addr parameter.
Otherwise, use common header to access type/length member.

Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/input.c b/net/sctp/input.c
index 5436c69..30cec77 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -1017,7 +1017,7 @@
 	/* Skip over the ADDIP header and find the Address parameter */
 	param = (union sctp_addr_param *)(asconf + 1);
 
-	af = sctp_get_af_specific(param_type2af(param->v4.param_hdr.type));
+	af = sctp_get_af_specific(param_type2af(param->p.type));
 	if (unlikely(!af))
 		return NULL;