CVE-2026-90213: firewire: core: fix memory leak in error path of build_tree()

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

firewire: core: fix memory leak in error path of buildtree()

In the error path of buildtree(), node instances can remain in the local linked list when the function returns.

Whenever an invalid value is detected in the self ID sequence, each allocated node instance is either an entry in the linked list or an entry in the ports array of its parent node. Therefore, the allocate node instances can be safely released by traversing the linked list from its head.

Release the remaining node instances with foreachfwnode() before returning to the caller.