rust_binder: clear freeze listener on node removal

In the Linux kernel, the following vulnerability has been resolved: rust_binder: clear freeze listener on node removal Generally userspace is supposed to explicitly clear freeze listeners before they drop the refcount on the node ref to zero, but there's nothing forcing that. Currently, in this scenario the freeze listener remains in the freeze_listeners rbtree and in the remote node's freeze listener list, even though the ref for which the listener is registered is gone. This could potentially lead to a memory leak due to a refcount cycle. Thus, remove the freeze listener in this scenario.