drm/panel: st7703: Add media bus format

This allows the DSI bridge to detect the correct bus format.
We currently only support MEDIA_BUS_FMT_RGB888_1X24.
Signed-off-by: Guido Günther <agx@sigxcpu.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/d7ebeec861f4518c8497a5e07d09d5a9fd123d3d.1633959458.git.agx@sigxcpu.org

drivers/gpu/drm/panel/panel-sitronix-st7703.c

@@ -453,6 +453,10 @@ static int st7703_prepare(struct drm_panel *panel)
 	return ret;
 }
 
+static const u32 mantix_bus_formats[] = {
+	MEDIA_BUS_FMT_RGB888_1X24,
+};
+
 static int st7703_get_modes(struct drm_panel *panel,
 			    struct drm_connector *connector)
 {
@@ -474,6 +478,10 @@ static int st7703_get_modes(struct drm_panel *panel,
 	connector->display_info.height_mm = mode->height_mm;
 	drm_mode_probed_add(connector, mode);
 
+	drm_display_info_set_bus_formats(&connector->display_info,
+					 mantix_bus_formats,
+					 ARRAY_SIZE(mantix_bus_formats));
+
 	return 1;
 }