sdl/events: change JoyDeviceAddedEvent's Which member to use JoystickID instead of int
sdl/events: change JoyDeviceAddedEvent's Which member to use JoystickID instead of int

Signed-off-by: Lilis Iskandar <f9acb790f2c75b127492316321ece0121b8eed9b@veand.co>

veandco/go-sdl2,veandco/go-sdl2