[FFmpeg-devel] swscale/x86/rgb2rgb : port shuffle2103 to external asm

[Martin Vignali]

>
> Keeping both MMX and MMXEXT seems a bit excessive. Ideally both would
> be replaced with something more modern, but I'd at least drop the MMX
> one.
>

This func already have SSSE3 version (AVX2 can be add easily, but doesn't
find a command line where the speed is interesting in AVX2 (on my
computer)).
I can remove mmx, and only keep mmxext, or remove both (but seems like not
everyone is agree to remove mmx/mmxext, if SSxx version is available).

Martin