boards: shields: st_lcd_dsi_mb1835: set LTDC pixel-format

Set zephyr_lcd_controller pixel-format to PANEL_PIXEL_FORMAT_ARGB_8888
to match the driver configuration.

Signed-off-by: Charles Dias <charlesdias.cd@outlook.com>

Author: CharlesDias

boards/shields/st_lcd_dsi_mb1835/st_lcd_dsi_mb1835.overlay

@@ -88,7 +88,7 @@
 	status = "okay";
 	width = <480>;
 	height = <480>;
-	pixel-format = <PANEL_PIXEL_FORMAT_RGB_888>;
+	pixel-format = <PANEL_PIXEL_FORMAT_ARGB_8888>;
 
 	bl-ctrl-gpios = <&dsi_lcd_qsh_030 53 GPIO_ACTIVE_HIGH>;