cxl: fix possible null-ptr-deref in cxlguestinit_afu|adapter()
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 v5.15.86 by commit e5021bbf11b024cc65ea1e84c377df484183be4b, it was introduced in version v4.6 by commit 14baf4d9c739e6e69150512d2eb23c71fffcc192. For more details please see the references link.