Set backlight status to on if it's at maximum brightness already and the brightness increase keybind is used

Before it was turned on but the status wasn't set to on, so you had to
push the backlight toggle bind twice to turn it off again

tmk_core/common/backlight.c

@@ -36,9 +36,9 @@ void backlight_increase(void)
     if(backlight_config.level < BACKLIGHT_LEVELS)
     {
         backlight_config.level++;
+    }
     backlight_config.enable = 1;
     eeconfig_update_backlight(backlight_config.raw);
-    }
     dprintf("backlight increase: %u\n", backlight_config.level);
     backlight_set(backlight_config.level);
 }