virtio-gpu-gl: declare dependency on ui-opengl

Since commit e8a2db94 "virtio-gpu-virgl: teach it to get the QEMU EGL
display", virtio-gl depends on ui-opengl symbol "qemu_egl_display".

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2391
Fixes: e8a2db94 ("virtio-gpu-virgl: teach it to get the QEMU EGL display")
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

hw/display/virtio-gpu-gl.c

@@ -170,3 +170,4 @@ static void virtio_register_types(void)
 type_init(virtio_register_types)
 
 module_dep("hw-display-virtio-gpu");
+module_dep("ui-opengl");