nfs4acls: Use an anon struct for SMB4ACL_T

nfs4acls: Use an anon struct for SMB4ACL_T

The relevant change:

-typedef struct _SMB4ACL_T {char dontuse;} SMB4ACL_T;
+struct SMB4ACL_T;

We can use anonymous structs to prevent direct use. This patch will
trigger a set of simplifications in the next patches

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>