drm/exynos: g2d: simplify g2d_free_runqueue_node()

The function is never called with zero 'runqueue_node'.
Signed-off-by: NTobias Jakobi <tjakobi@math.uni-bielefeld.de>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_g2d.c

@@ -845,9 +845,6 @@ static void g2d_free_runqueue_node(struct g2d_data *g2d,
 {
 	struct g2d_cmdlist_node *node;
 
-	if (!runqueue_node)
-		return;
-
 	mutex_lock(&g2d->cmdlist_mutex);
 	/*
 	 * commands in run_cmdlist have been completed so unmap all gem