net/mlx5e: CT: Fix queued up restore put() executing after relevant ft release

commit b069e14f upstream.

__mlx5_tc_ct_entry_put() queues release of tuple related to some ct FT,
if that is the last reference to that tuple, the actual deletion of
the tuple can happen after the FT is already destroyed and freed.

Flush the used workqueue before destroying the ct FT.

Fixes: a2173131 ("net/mlx5e: CT: manage the lifetime of the ct entry object")
Reviewed-by: Oz Shlomo <ozsh@nvidia.com>
Signed-off-by: Paul Blakey <paulb@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>