mlxsw: spectrum_switchdev: remove transactional logic for VLAN objects

As of commit 457e20d6 ("mlxsw: spectrum_switchdev: Avoid returning
errors in commit phase"), the mlxsw driver performs the VLAN object
offloading during the prepare phase. So conversion just seems to be a
matter of removing the code that was running in the commit phase.

Ido Schimmel explains that the reason why mlxsw_sp_span_respin is called
unconditionally is because the bridge driver will ignore -EOPNOTSUPP and
actually add the VLAN on the bridge device - see commit 9c86ce2c
("net: bridge: Notify about bridge VLANs") and commit ea472175


("mlxsw: spectrum_switchdev: Ignore bridge VLAN events"). Since the VLAN
was successfully added on the bridge device, mlxsw_sp_span_respin_work()
should be able to resolve the egress port for a packet that is mirrored
to a gre tap and passes through the bridge device. Therefore keep the
logic as it is.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>