drm/bridge: lt8912b: set hdmi or dvi mode

The Lontium LT8912 does have a setting for DVI or HDMI. This patch reads
from EDID what the display needs and sets it accordingly.

Fixes: 30e2ae94 ("drm/bridge: Introduce LT8912B DSI to HDMI bridge")
Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Acked-by: Adrien Grassein <adrien.grassein@gmail.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220922124306.34729-3-dev@pschenker.ch

drivers/gpu/drm/bridge/lontium-lt8912b.c

@@ -323,6 +323,8 @@ static int lt8912_video_setup(struct lt8912 *lt)
 				  vsync_activehigh ? BIT(0) : 0);
 	ret |= regmap_update_bits(lt->regmap[I2C_MAIN], 0xab, BIT(1),
 				  hsync_activehigh ? BIT(1) : 0);
+	ret |= regmap_update_bits(lt->regmap[I2C_MAIN], 0xb2, BIT(0),
+				  lt->connector.display_info.is_hdmi ? BIT(0) : 0);
 
 	return ret;
 }