drm/exynos/decon5433: kill DECON_UPDATE workaround

Since fixing CMU code (drm/exynos/decon5433: fix CMU programming)
DECON started behave predictable and does not need special care
during DECON_UPDATE writes.
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos5433_drm_decon.c

@@ -51,8 +51,7 @@ enum decon_flag_bits {
 	BIT_CLKS_ENABLED,
 	BIT_IRQS_ENABLED,
 	BIT_WIN_UPDATED,
-	BIT_SUSPENDED,
-	BIT_REQUEST_UPDATE
+	BIT_SUSPENDED
 };
 
 struct decon_context {
@@ -399,7 +398,6 @@ static void decon_update_plane(struct exynos_drm_crtc *crtc,
 
 	/* window enable */
 	decon_set_bits(ctx, DECON_WINCONx(win), WINCONx_ENWIN_F, ~0);
-	set_bit(BIT_REQUEST_UPDATE, &ctx->flags);
 }
 
 static void decon_disable_plane(struct exynos_drm_crtc *crtc,
@@ -412,7 +410,6 @@ static void decon_disable_plane(struct exynos_drm_crtc *crtc,
 		return;
 
 	decon_set_bits(ctx, DECON_WINCONx(win), WINCONx_ENWIN_F, 0);
-	set_bit(BIT_REQUEST_UPDATE, &ctx->flags);
 }
 
 static void decon_atomic_flush(struct exynos_drm_crtc *crtc)
@@ -429,7 +426,6 @@ static void decon_atomic_flush(struct exynos_drm_crtc *crtc)
 	for (i = ctx->first_win; i < WINDOWS_NR; i++)
 		decon_shadow_protect_win(ctx, i, false);
 
-	if (test_and_clear_bit(BIT_REQUEST_UPDATE, &ctx->flags))
 	decon_set_bits(ctx, DECON_UPDATE, STANDALONE_UPDATE_F, ~0);
 
 	if (ctx->out_type & IFTYPE_I80)