v3dv: display fd initialization fixes
This moves display_fd acquisition to swapchain creation time (while adding a workaroud for Zink, which doesn't use swapchains), looking at the enabled extensions in the instance to decide how to acquire an authenticated device.
This also fixes a regression introduced with the implementation of VK_KHR_display where if this extension was enabled but we were running inside a compositor, we would not try to get an authenticated display device from the compositor and would assume that our display_fd was a master.