efi: fix potential NULL deref in efimemreserve_persistent
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 v5.15.93 by commit d8fc0b5fb3e816a4a8684bcd3ed02cbef0fce23c, it was introduced in version v5.2 by commit 18df7577adae6c6c778bf774b3aebcacbc1fb439. For more details please see the references link.