vulkan/wsi: unbreak win32-support
There's no unistd.h on Windows, let's not include it unconditionally.
But we also don't want to deal with DRM modifiers or DMABUFs on Windows, so let's also ifdef out the rest of that stuff.
Fixes: a8b009ae ("vulkan/wsi: fix missing unistd include") Fixes: c72ff19a ("vulkan/wsi: Close file descriptors in wsi_destroy_image")