CVE-2026-89674 nfsd: fix XDR length calculation in nfsd4_ff_encode_layoutget

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix XDR length calculation in nfsd4ffencodelayoutget The XDR buffer size calculation in nfsd4ffencodelayoutget has multiple errors that can result in either an out-of-bounds write or leaking uninitialized kernel memory to t...