GSD-2022-1005961 um: add "noreboot" command line option for PANIC_TIMEOUT=-1 setups

um: add "noreboot" command line option for PANICTIMEOUT=-1 setups 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 v5.4.211 by commit...