CVE-2025-68804

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

platform/chrome: cros_ec_ishtp: Fix UAF after unbinding driver

After unbinding the driver, another kthread `cros_ec_console_log_work`
is still accessing the device, resulting an UAF and crash.

The driver doesn't unregister the EC device in .remove() which should
shutdown sub-devices synchronously.  Fix it.