cifs: clarify SMB1 code for UnixCreateHardLink

Coverity complains about the way we calculate the offset
(starting from the address of a 4 byte array within the
header structure rather than from the beginning of the struct
plus 4 bytes).  This doesn't change the address but
makes it slightly clearer.

Addresses-Coverity: 711529 ("Out of bounds read")
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
diff --git a/fs/cifs/cifspdu.h b/fs/cifs/cifspdu.h
index 0923f72..f6e2350 100644
--- a/fs/cifs/cifspdu.h
+++ b/fs/cifs/cifspdu.h
@@ -1785,6 +1785,7 @@ struct smb_com_transaction2_sfi_req {
 	__u16 Fid;
 	__le16 InformationLevel;
 	__u16 Reserved4;
+	__u8  payload[];
 } __attribute__((packed));
 
 struct smb_com_transaction2_sfi_rsp {