DEBIAN-CVE-2026-64410

In the Linux kernel, the following vulnerability has been resolved:  netfilter: flowtable: IPIP tunnel hardware offload is not yet support  No driver supports for IPIP tunnels yet, give up early on setting up the hardware offload for this scenario.  This patch adds a stub that can be enhanced to add more configuration that are currently not supported. As of now, the offload work is enqueued to the worker, then ignored if the hardware offload configuration is not supported.  Check the NFFLOWHW flag to know if this entry was already tried once to be offloaded so this is not retried on refresh when unsupported. Move NFFLOWHW flag check to nfflowoffloadadd(). If this NFFLOWHW flag is unset the del and _stats variants are never called.  This can be updated later on to skip hardware offload work to be queued in case hardware offload does not support it.