Remove no longer required SDL2 P/Invokes in Linux clipboard
Remove no longer required SDL2 P/Invokes in Linux clipboard

peppy/osu-framework,ppy/osu-framework,peppy/osu-framework,peppy/osu-framework,ppy/osu-framework,smoogipooo/osu-framework,ppy/osu-framework,smoogipooo/osu-framework