revert devicescreen

Runtime/Plugins/platform/ios/DeviceScreen.mm

 #import <UIKit/UIKit.h>
 extern "C"
 {
-int IOSDeviceScaleFactor()
-{
-return [[UIScreen mainScreen] scale];
-}
+    int IOSDeviceScaleFactor()
+    {
+        return [[UIScreen mainScreen] scale];
+    }
 }