net/mlx4: fix rescheduled link status check

net/mlx4: fix rescheduled link status check

Link status is sometimes inconsistent during a LSC event. When it occurs,
the PMD refrains from immediately notifying the application; instead, an
alarm is scheduled to check link status later and notify the application
once it has settled.

The problem is that subsequent link status checks are only performed if
additional LSC events occur in the meantime, which is not always the case.

Worse, since support for removal events was added, rescheduled link status
checks may consume them as well without notifying the application. With the
right timing, a link loss occurring just before a device removal event may
hide it from the application.

Fixes: 6dd7b7056d7f ("net/mlx4: support device removal event")
Fixes: 2d449f7c52de ("net/mlx4: fix assertion failure on link update")
Cc: stable@dpdk.org
Reported-by: Matan Azrad <matan@mellanox.com>
Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>