drm/omap: fix bus_flags for panel-dpi

panel-dpi used to convey the bus-flags via the videomode, but recent
changes changed the use of videomode to DRM's drm_display_mode which
does not contain bus-flags. This broke panel-dpi, which didn't
explicitly store the bus-flags into dssdev->bus_flags.

Fix this by setting dssdev->bus_flags. Also change the bus_flags type to
u32, as that is the type used in the DRM framework, and we would get a
warning with drm_bus_flags_from_videomode() otherwise.

Fixes: 3fbda31e814868d8477ddf52d74b7b8f596578e8 ("drm/omap: Split mode fixup and mode set from encoder enable")
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reported-by: H. Nikolaus Schaller <hns@goldelico.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181126092447.11864-1-tomi.valkeinen@ti.com
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

drivers/gpu/drm/omapdrm/displays/panel-dpi.c

@@ -177,6 +177,7 @@ static int panel_dpi_probe(struct platform_device *pdev)
 	dssdev->type = OMAP_DISPLAY_TYPE_DPI;
 	dssdev->owner = THIS_MODULE;
 	dssdev->of_ports = BIT(0);
+	drm_bus_flags_from_videomode(&ddata->vm, &dssdev->bus_flags);
 
 	omapdss_display_init(dssdev);
 	omapdss_device_register(dssdev);

drivers/gpu/drm/omapdrm/dss/omapdss.h

@@ -432,7 +432,7 @@ struct omap_dss_device {
 	const struct omap_dss_driver *driver;
 	const struct omap_dss_device_ops *ops;
 	unsigned long ops_flags;
-	unsigned long bus_flags;
+	u32 bus_flags;
 
 	/* helper variable for driver suspend/resume */
 	bool activate_after_resume;