GSD-2022-1000059 nitro_enclaves: Use get_user_pages_unlocked() call to handle mmap assert

nitroenclaves: Use getuserpagesunlocked call to handle mmap assert 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 v5.15.13 by commit...