CVE-2024-46697 nfsd: ensure that nfsd4_fattr_args.context is zeroed out

In the Linux kernel, the following vulnerability has been resolved: nfsd: ensure that nfsd4fattrargs.context is zeroed out If nfsd4encodefattr4 ends up doing a "goto out" before we get to checking for the security label, then args.context will be set to uninitialized junk on the stack, which we'l...