CVE-2022-48759 rpmsg: char: Fix race between the release of rpmsg_ctrldev and cdev

In the Linux kernel, the following vulnerability has been resolved: rpmsg: char: Fix race between the release of rpmsgctrldev and cdev struct rpmsgctrldev contains a struct cdev. The current code frees the rpmsgctrldev struct in rpmsgctrldevreleasedevice, but the cdev is a managed object, therefo...