net/mlx5: Rework handling of port module events

Add explicit HW defined error values. For simplicity, keep counters for all
statuses starting from 0, although currently status=0 is not used.

Additionally, when HW signals an unexpected cable status, it is reported
now rather than ignored. And status counter is now updated on errors.

Signed-off-by: Mikhael Goikhman <migo@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>