CVE-2024-27063: leds: trigger: netdev: Fix kernel panic on interface rename trig notify

In the Linux kernel, the following vulnerability has been resolved:

leds: trigger: netdev: Fix kernel panic on interface rename trig notify

Commit d5e01266e7f5 ("leds: trigger: netdev: add additional specific link speed mode") in the various changes, reworked the way to set the LINKUP mode in commit cee4bd16c319 ("leds: trigger: netdev: Recheck NETDEVLEDMODELINKUP on dev rename") and moved it to a generic function.

This changed the logic where, in the previous implementation the dev from the trigger event was used to check if the carrier was ok, but in the new implementation with the generic function, the dev in triggerdata is used instead.

This is problematic and cause a possible kernel panic due to the fact that the dev in the triggerdata still reference the old one as the new one (passed from the trigger event) still has to be hold and saved in the triggerdata struct (done in the NETDEVREGISTER case).

On calling of getdevicestate(), an invalid netdev is used and this cause a kernel panic.

To handle this correctly, move the call to getdevicestate() after the new netdev is correctly set in triggerdata (in the NETDEVREGISTER case) and correctly parse the new dev.