net/failsafe: fix removed sub-device cleanup

net/failsafe: fix removed sub-device cleanup

The fail-safe PMD registers to RMV event for each removable sub-device
port in order to cleanup the sub-device resources and switch the Tx
sub-device directly when it is plugged-out.

During removal time, the fail-safe PMD stops and closes the sub-device
but it doesn't unregister the LSC and RMV callbacks of the sub-device
port.

It can lead the callbacks to be called for a port which is no more
associated with the fail-safe sub-device, because there is not a
guarantee that a sub-device gets the same port ID for each plug-in
process. This port, for example, may belong to another sub-device of a
different fail-safe device.

Unregister the LSC and RMV callbacks for sub-devices which are not
used.

Fixes: 598fb8aec6f6 ("net/failsafe: support device removal")
Cc: stable@dpdk.org
Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Gaetan Rivet <gaetan.rivet@6wind.com>