mlxsw: spectrum: Default ports to non-virtual mode

In virtual mode, packets are classified to FIDs based on their ingress
port and VLAN whereas in non-virtual mode only the VLAN is taken into
account.

Currently ports are initialized to use virtual mode due to the presence
of the PVID vPort. However, we're going to transition ports between both
modes based on the FIDs they use and not merely based on the presence on
a VLAN upper. Therefore, during initialization, no mode will be
explicitly set.

Since the Programmer's Reference Manual (PRM) doesn't specify a default,
explicitly set the port to non-virtual mode and later transition the
port between both modes based on the FIDs it uses.

In a follow-up patchset, this step will be moved to the common FID core
where it logically belongs.

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>