net/mlx5: fix initial link status detection

net/mlx5: fix initial link status detection

Link status change takes time that depends on the HW and the kernel.
It was checked immediately after the change was issued at probing.
If the port had been down before probing, a "down" state may be read,
while the port would be "up" imminently.
After that, DPDK reported the port as "down" mistakenly
and "ifconfig $DEV up" did not trigger an LSC event,
because from the system's perspective the port was "up" already.

Install Netlink event handler at port probe before requesting the port
to come up in order to receive LSC event even if it comes up
between probe and start.

Fixes: a85a606ca501 ("net/mlx5: fix link status initialization")
Cc: stable@dpdk.org
Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Reviewed-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>