Backlight control

• moved PWM_Output content from lib/card10/display.c to DEV_Set_BL in lib/gfx/GUI_DEV/DEV_config.c (activating LCD_SetBacklight, which uses it)
• added epic_disp_backlight, which calls LCD_SetBacklight
• added backlight() to pycardium display module, making backlight available to py apps

epicardium/modules/display.c

@@ -171,6 +171,17 @@ int epic_disp_framebuffer(union disp_framebuffer *fb)
 	return 0;
 }
 
+int epic_disp_backlight(uint16_t brightness)
+{
+	int cl = check_lock();
+	if (cl < 0) {
+		return cl;
+	}
+
+	LCD_SetBacklight(brightness);
+	return 0;
+}
+
 int epic_disp_open()
 {
 	TaskHandle_t task = xTaskGetCurrentTaskHandle();