mlxsw: spectrum_router: Adjust RIF configuration for new firmware versions

In new firmware versions, when configuring a {Port, VID} as a router
interface, the driver is responsible for enabling the STP filter and
disabling learning.  Otherwise, packets are discarded.

This change doesn't break existing firmware versions, but is required
for newer firmware versions.

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