When changing eswitch mode, the netdev is detached from the
hardware resources. So verify dev is present in get devlink
port ndo. Otherwise, we will hit the following panic:
Fixes: 2ff349c5edfe ("net/mlx5e: Verify dev is present in some ndos") Signed-off-by: Roi Dayan <roid@nvidia.com> Signed-off-by: Chris Mi <cmi@nvidia.com> Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>