drm/panel: vtdr6130: Use 16-bit brightness function

This panel communicates brightness in big endian. This is not a quirk of
the panels themselves, but rather, a part of the MIPI standard. Use the
new mipi_dsi_dcs_set_display_brightness_large() function that properly
handles 16-bit brightness instead of bypassing the brightness functions
entirely.

Signed-off-by: Richard Acayan <mailingradian@gmail.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-MTP
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230116224909.23884-4-mailingradian@gmail.com

Author: flamingradian

drivers/gpu/drm/panel/panel-visionox-vtdr6130.c

@@ -243,12 +243,9 @@ static int visionox_vtdr6130_bl_update_status(struct backlight_device *bl)
 {
 	struct mipi_dsi_device *dsi = bl_get_data(bl);
 	u16 brightness = backlight_get_brightness(bl);
-	/* Panel needs big-endian order of brightness value */
-	u8 payload[2] = { brightness >> 8, brightness & 0xff };
 	int ret;
 
-	ret = mipi_dsi_dcs_write(dsi, MIPI_DCS_SET_DISPLAY_BRIGHTNESS,
-				 payload, sizeof(payload));
+	mipi_dsi_dcs_set_display_brightness_large(dsi, brightness);
 	if (ret < 0)
 		return ret;