d3d: Avoid rewriting textures to BGRA from RGBA, just swizzle

In Direct3D, the order is already the same.  We don't need to redo the clut or textures or anything, so we can save a bit of copying and cut down on some code.

I was hoping for better, but it only gave a 1-2% improvement in FF2, so probably way less in most games.

-[Unknown]