Support for DRM_IOCTL_WAIT_VBLANK on Linux driver

See https://github.com/WebKit/WebKit/pull/17856

In WebKitGTK, a port of the WebKit web engine for Linux which is used by Epiphany (Gnome Web), Tauri and Gnome platform WebView, the DisplayLink feature is implemented with DRM_IOCTL_WAIT_VBLANK on Intel and AMD hardware. However, this is not exposed in Nvidia drivers, so WebKitGTK does not know when the screen refreshes, and has to fall back to a timer-based approach to update screen content. This is not ideal as the DRM-based approach offer better rendering performance. It would be much appreciated if the Nvidia drivers could expose vblank signals.