dm integrity: Fix UAF in dmintegritydtr()
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v5.15.87 by commit 9215b25f2e105032114e9b92c9783a2a84ee8af9, it was introduced in version v4.12 by commit 7eada909bfd7ac90a4522e56aa3179d1fd68cd14. For more details please see the references link.