GSD-2022-1000916 xen/netfront: react properly to failing gnttab_end_foreign_access_ref()

xen/netfront: react properly to failing gnttabendforeignaccessref 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 v4.14.271 by commit...