drm/exynos: dsi: move DSIM_STATE_ENABLED set position

The command mode panel should draw image earlier than the display
on command execution to prevent showing garbage GRAM screen data.
So should set dsi->state as DSIM_STATE_ENABLED between calling
exynos_dsi_set_display_enable() and drm_panel_enable() to transmit
image data before executing display on command.
And moves the display on command execution routine from prepare()
to enable() in drm_panel_funcs also.

Signed-off-by: YoungJun Cho <yj44.cho@samsung.com>
Acked-by: Inki Dae <inki.dae@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_dsi.c

@@ -1381,16 +1381,17 @@ static int exynos_dsi_enable(struct exynos_dsi *dsi)
 	exynos_dsi_set_display_mode(dsi);
 	exynos_dsi_set_display_enable(dsi, true);
 
+	dsi->state |= DSIM_STATE_ENABLED;
+
 	ret = drm_panel_enable(dsi->panel);
 	if (ret < 0) {
+		dsi->state &= ~DSIM_STATE_ENABLED;
 		exynos_dsi_set_display_enable(dsi, false);
 		drm_panel_unprepare(dsi->panel);
 		exynos_dsi_poweroff(dsi);
 		return ret;
 	}
 
-	dsi->state |= DSIM_STATE_ENABLED;
-
 	return 0;
 }