Moves render target restoring to RestoreAPIState, this also means no need
to manually restore after allocating in a buffer that caused execution,
because the manager restores it for us.
Remove a method that wasn't used from D3DUtil.cpp, and fixes a few errors
in EFB poke drawing.
- remove an outdated comment about the efb to ram and scaled efb restriction
- when upscaling efb copies, mark the new texture as efb copy
- dx12 fixes for the src box, especially the number of layers for 3D
