scm: remove use CMSG{_COMPAT}_ALIGN(sizeof(struct {compat_}cmsghdr))

sizeof(struct cmsghdr) and sizeof(struct compat_cmsghdr) already aligned.
remove use CMSG_ALIGN(sizeof(struct cmsghdr)) and
CMSG_COMPAT_ALIGN(sizeof(struct compat_cmsghdr)) keep code consistent.

Signed-off-by: yuan linyu <Linyu.Yuan@alcatel-sbell.com.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index cf9b43de..1caa38d 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -272,7 +272,7 @@ int ip_cmsg_send(struct sock *sk, struct msghdr *msg, struct ipcm_cookie *ipc,
 			continue;
 		switch (cmsg->cmsg_type) {
 		case IP_RETOPTS:
-			err = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
+			err = cmsg->cmsg_len - sizeof(struct cmsghdr);
 
 			/* Our caller is responsible for freeing ipc->opt */
 			err = ip_options_get(net, &ipc->opt, CMSG_DATA(cmsg),