sdl: mouse.go: Add fallback definitions for SDL_MOUSEWHEEL_NORMAL and SDL_MOUSEWHEEL_FLIPPED
sdl: mouse.go: Add fallback definitions for SDL_MOUSEWHEEL_NORMAL and SDL_MOUSEWHEEL_FLIPPED

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

veandco/go-sdl2,veandco/go-sdl2