sctp: Fix out-of-bounds warning in sctp_process_asconf_param()

Fix the following out-of-bounds warning:

net/sctp/sm_make_chunk.c:3150:4: warning: 'memcpy' offset [17, 28] from the object at 'addr' is out of the bounds of referenced subobject 'v4' with type 'struct sockaddr_in' at offset 0 [-Warray-bounds]

This helps with the ongoing efforts to globally enable -Warray-bounds
and get us closer to being able to tighten the FORTIFY_SOURCE routines
on memcpy().

Link: KSPP/linux#109
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/sm_make_chunk.c

@@ -3147,7 +3147,7 @@ static __be16 sctp_process_asconf_param(struct sctp_association *asoc,
 		 * primary.
 		 */
 		if (af->is_any(&addr))
-			memcpy(&addr.v4, sctp_source(asconf), sizeof(addr));
+			memcpy(&addr, sctp_source(asconf), sizeof(addr));
 
 		if (security_sctp_bind_connect(asoc->ep->base.sk,
 					       SCTP_PARAM_SET_PRIMARY,