During ISSU, "mlxsw_minimal" driver still trying to access firmware, in some cases FW could return some wrong critical threshold value which will cause switch shutdown.
**- How I did it**
In order to prevent "mlxsw_minimal" driver from accessing ASIC during ISSU, SDK will raise "OFFLINE" 'udev' event
at the early beginning of such flow. When this event is received, hw-management will remove "mlxsw_minimal" driver.
There is no need to implement the opposite "ONLINE" event since this flow is ended up with "kexec".
**- How to verify it**
repeatedly perform warm reboot, make sure there is no switch shutdown occurred.
