net/mlx5: DR, Fix the SMFS sync_steering for fast teardown

If sync happens when the device is in fast teardown, just bail
and don't do anything, because the PCI device is not there any more.

Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: Alex Vesker <valex@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>