Use VFIO PCI IDs to bind specific GPUs in multi-GPU systems

With multiple NVIDIA GPUs, use vfio-pci ids= with specific device IDs in /etc/modprobe.d/vfio.conf plus 'softdep nvidia pre: vfio-pci' to ensure VFIO claims the target GPU before nvidia claims all of them. This lets one GPU go to a VM while others stay available for LXC passthrough.

Config at /etc/modprobe.d/vfio.conf:\n```\noptions vfio-pci ids=10de:2484,10de:228b\nsoftdep nvidia pre: vfio-pci\n```\n\nThe softdep ensures vfio-pci loads before nvidia. VFIO claims the 3070 by PCI ID, nvidia then only finds the P4.\n\nAfter update-initramfs and reboot:\n- RTX 3070: vfio-pci (for VM passthrough)\n- Tesla P4: nvidia (for LXC/Jellyfin)\n\nDiscovered during Windows VM deployment (2026-04-13).