vmwgfx: drop empty lastclose stub

Core DRM is safe when the callback is NULL.

Cc: VMware Graphics <linux-graphics-maintainer@vmware.com>
Cc: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190522164119.24139-1-emil.l.velikov@gmail.com

drivers/gpu/drm/vmwgfx/vmwgfx_drv.c

@@ -1177,10 +1177,6 @@ static long vmw_compat_ioctl(struct file *filp, unsigned int cmd,
 }
 #endif
 
-static void vmw_lastclose(struct drm_device *dev)
-{
-}
-
 static void vmw_master_init(struct vmw_master *vmaster)
 {
 	ttm_lock_init(&vmaster->lock);
@@ -1551,7 +1547,6 @@ static struct drm_driver driver = {
 	DRIVER_MODESET | DRIVER_RENDER | DRIVER_ATOMIC,
 	.load = vmw_driver_load,
 	.unload = vmw_driver_unload,
-	.lastclose = vmw_lastclose,
 	.get_vblank_counter = vmw_get_vblank_counter,
 	.enable_vblank = vmw_enable_vblank,
 	.disable_vblank = vmw_disable_vblank,