drm/panel: simple: Add bus format for HannStar HSD070PWW1 LVDS panel

The bus format both specifies the bpc and the way the individual bits get
serialized into the 7 LVDS timeslots.

While the is only one standard mapping for 6 bpc and so the driver could
infer the bit mapping from the bpc alone, there are more options for the
8 bpc case which makes specifiying the bus format mandatory.
To keep things consistent across panels and to set a precedent for new
panel additions add the proper bus format.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/panel/panel-simple.c

@@ -729,6 +729,7 @@ static const struct panel_desc hannstar_hsd070pww1 = {
 		.width = 151,
 		.height = 94,
 	},
+	.bus_format = MEDIA_BUS_FMT_RGB666_1X7X3_SPWG,
 };
 
 static const struct display_timing hannstar_hsd100pxn1_timing = {