drm/exynos/mixer: always update INT_EN cache

INT_EN cache field was updated only by mixer_enable_vblank.
The patch adds update also by mixer_disable_vblank function.
Signed-off-by: NAndrzej Hajda <a.hajda@samsung.com>
Reviewed-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_mixer.c

@@ -917,6 +917,11 @@ static void mixer_disable_vblank(struct exynos_drm_crtc *crtc)
 	struct mixer_context *mixer_ctx = crtc->ctx;
 	struct mixer_resources *res = &mixer_ctx->mixer_res;
 
+	if (!mixer_ctx->powered) {
+		mixer_ctx->int_en &= MXR_INT_EN_VSYNC;
+		return;
+	}
+
 	/* disable vsync interrupt */
 	mixer_reg_writemask(res, MXR_INT_STATUS, ~0, MXR_INT_CLEAR_VSYNC);
 	mixer_reg_writemask(res, MXR_INT_EN, 0, MXR_INT_EN_VSYNC);