drm: panel: simple-panel: add bus format information for foxlink panel

Foxlink's fl500wvr00-a0t supports RGB888 format.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index 4504018..6049d24 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -563,6 +563,7 @@
 		.width = 108,
 		.height = 65,
 	},
+	.bus_format = MEDIA_BUS_FMT_RGB888_1X24,
 };
 
 static const struct drm_display_mode hannstar_hsd070pww1_mode = {