drm/imx: convey the pixelclk-active and de-active flags from DT to the ipu-di driver

The 'de-active' and 'pixelclk-active' DT properties are evaluated
by of_parse_display_timing() called from  of_get_drm_display_mode(),
but later lost in the conversion from videomode.flags to
drm_display_mode.flags.
Enhance of_get_drm_display_mode() to also return the bus flags in a
separate variable, so that they can be passed on to the ipu-di
driver.

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 51804e5..1570487 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -687,7 +687,8 @@
  * 0 on success, a negative errno code when no of videomode node was found.
  */
 int of_get_drm_display_mode(struct device_node *np,
-			    struct drm_display_mode *dmode, int index)
+			    struct drm_display_mode *dmode, u32 *bus_flags,
+			    int index)
 {
 	struct videomode vm;
 	int ret;
@@ -697,6 +698,8 @@
 		return ret;
 
 	drm_display_mode_from_videomode(&vm, dmode);
+	if (bus_flags)
+		drm_bus_flags_from_videomode(&vm, bus_flags);
 
 	pr_debug("%s: got %dx%d display mode from %s\n",
 		of_node_full_name(np), vm.hactive, vm.vactive, np->name);