cifs: create sd context must be a multiple of 8

We used to follow the rule earlier that the create SD context
always be a multiple of 8. However, with the change:
cifs: refactor create_sd_buf() and and avoid corrupting the buffer
...we recompute the length, and we failed that rule.
Fixing that with this change.

Cc: <stable@vger.kernel.org> # v5.10+
Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/smb2pdu.c

@@ -2426,7 +2426,7 @@ create_sd_buf(umode_t mode, bool set_owner, unsigned int *len)
 	memcpy(aclptr, &acl, sizeof(struct cifs_acl));
 
 	buf->ccontext.DataLength = cpu_to_le32(ptr - (__u8 *)&buf->sd);
-	*len = ptr - (__u8 *)buf;
+	*len = roundup(ptr - (__u8 *)buf, 8);
 
 	return buf;
 }