net/mlx5: link status update separation

net/mlx5: link status update separation

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.

In the previous code the alarm callback calls to the interrupt
handler for link status recheck and may cause to unnecessary
interrupt events check.

This patch separates the link status update and the interrupt event
handler to avoid the unnecessary check and arranges the interrupt
handler for more interrupt supports in the future.

Comment was added in the new function to explain the inconsistent
link status reason.

Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>