nvk: First round of WSI enablement
This enables WSI for NVK. Currently, it always gets the blit path and renders correctly on X11 and corrupts on Wayland. The problem is that we don't yet support linear images so wayland gets tiled and is wrong. The thing that saves us for X11 is the lack of VK_EXT_pci_bus_info.
Edited by Faith Ekstrand