CVE-2024-53184 um: ubd: Do not use drvdata in release

In the Linux kernel, the following vulnerability has been resolved: um: ubd: Do not use drvdata in release The drvdata is not available in release. Let's just use containerof to get the ubd instance. Otherwise, removing a ubd device will result in a crash: RIP: 0033:blkmqfreetagset+0x1f/0xba RSP:...