net/mlx5: fix DevX event registration timing

net/mlx5: fix DevX event registration timing

The DevX counter management triggers an asynchronous event to get back
the new counters values from the HW.

The counter management doesn't trigger 2 parallel events for the same
pool, hence, the pool cannot be updated again in the event waiting time.

When the port is stopped, the DevX event mechanism wrongly was
destroyed what remained all the waiting pools in waiting state forever.

As a result, the counters of the stuck pools were never updated again.

Separate the DevX interrupt installation from the dev installation and
remove the DevX interrupt unregistration\registration from the
stop\start operations.

Now, the DevX interrupt should be installed in probe and uninstalled in
close.

Cc: stable@dpdk.org
Fixes: f15db67df09c ("net/mlx5: accelerate DV flow counter query")

Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>