mlxsw: core: Remove priv from listener equality comparison

During packet receive, only the first matching RX listener
in rx_listener_list is going to get the packet. So there is no
meaning in registering two equal listeners with different privs.
Remove priv from equality comparison and disable possibility
of doing it.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>