stcp: Use memset_after() to zero sctp_stream_out_ext

Use memset_after() helper to simplify the code, there is no functional
change in this patch.
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Link: https://lore.kernel.org/r/20220519062932.249926-1-xiujianfeng@huawei.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/sctp/stream_sched.c

@@ -146,14 +146,11 @@ int sctp_sched_set_sched(struct sctp_association *asoc,
 
 		/* Give the next scheduler a clean slate. */
 		for (i = 0; i < asoc->stream.outcnt; i++) {
-			void *p = SCTP_SO(&asoc->stream, i)->ext;
+			struct sctp_stream_out_ext *ext = SCTP_SO(&asoc->stream, i)->ext;
 
-			if (!p)
+			if (!ext)
 				continue;
-
-			p += offsetofend(struct sctp_stream_out_ext, outq);
-			memset(p, 0, sizeof(struct sctp_stream_out_ext) -
-				     offsetofend(struct sctp_stream_out_ext, outq));
+			memset_after(ext, 0, outq);
 		}
 	}