net/mlx5: Separate probe vs. reload flows

The mix between probe/unprobe and reload flows causes to have an extra
mutex lock intf_state_mutex that generates LOCKDEP warning between it
and devlink_mutex. As a preparation for the future removal, separate
those flows.

Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>