drm/exynos: allow multiple layer updates per vsync for mixer

Allowing only one layer update per vsync can cause issues
while there are update available for both layers. There is
a good amount of possibility to loose updates if we allow
single update per vsync.
Signed-off-by: NRahul Sharma <rahul.sharma@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_mixer.c

@@ -511,13 +511,8 @@ static void vp_video_buffer(struct mixer_context *ctx, int win)
 static void mixer_layer_update(struct mixer_context *ctx)
 {
 	struct mixer_resources *res = &ctx->mixer_res;
-	u32 val;
-
-	val = mixer_reg_read(res, MXR_CFG);
 
-	/* allow one update per vsync only */
-	if (!(val & MXR_CFG_LAYER_UPDATE_COUNT_MASK))
-		mixer_reg_writemask(res, MXR_CFG, ~0, MXR_CFG_LAYER_UPDATE);
+	mixer_reg_writemask(res, MXR_CFG, ~0, MXR_CFG_LAYER_UPDATE);
 }
 
 static void mixer_graph_buffer(struct mixer_context *ctx, int win)