net/mlx5: E-switch, Fix switchdev mode after devlink reload

net/mlx5: E-switch, Fix switchdev mode after devlink reload

[ Upstream commit 7c83d1f4c5adae9583e7fca1e3e830d6b061522d ]

The cited commit removes eswitch mode none. So after devlink reload
in switchdev mode, eswitch mode is not changed. But actually eswitch
is disabled during devlink reload.

Fix it by setting eswitch mode to legacy when disabling eswitch
which is called by reload_down.

Fixes: b4deb7a001e6 ("net/mlx5: E-switch, Remove dependency between sriov and eswitch mode")
Signed-off-by: Chris Mi <cmi@nvidia.com>
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>