drm/bridge: tc358767: give VSDELAY some positive value

The documentation is not clear about how this delay works.
Empirical tests have shown that with a VSDELAY of 0, the first
scanline is not properly formatted in the output stream when
DSI->DP mode is used. The calculation spreadsheets from Toshiba
seem to always make this value equal to the HFP + 10 for DSI->DP
use-case. For DSI->DPI this value should be > 2 and for DPI->DP
it seems to always be 0x64.
Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Tested-by: Marek Vasut <marex@denx.de> # TC9595
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230721165328.3968759-2-l.stach@pengutronix.de

drivers/gpu/drm/bridge/tc358767.c

@@ -817,7 +817,7 @@ static int tc_set_common_video_mode(struct tc_data *tc,
 	 * sync signals
 	 */
 	ret = regmap_write(tc->regmap, VPCTRL0,
-			   FIELD_PREP(VSDELAY, 0) |
+			   FIELD_PREP(VSDELAY, right_margin + 10) |
 			   OPXLFMT_RGB888 | FRMSYNC_DISABLED | MSF_DISABLED);
 	if (ret)
 		return ret;