CVE-2026-98587: firewire: cdev: fix back-transition for iso_resource_auto client resource

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

firewire: cdev: fix back-transition for isoresourceauto client resource

The todo member of isoresourceauto structure represents the state of the client resource and normally transitions in the following order:

ISORESAUTOALLOC -> ISORESAUTOREALLOC -> ISORESAUTODEALLOC

However, concurrent access from the work item and the file descriptor release function can cause the state to transition backwards from ISORESAUTODEALLOC to ISORESAUTOREALLOC.

Prevent the back-transition by checking the current state before updating it in the work item.