deinterlace: purge MMX/MMXEXT
Per the request in MR !55 to split things out such that the android build issue for the new deinterlace SSE2 code does not hold up the purge, I have reworked the deinterlace changes. Here we purge the MMX/MMXEXT code, and make a small correction to use of emms
with SSE code. This leaves us with no acceleration for portions of deinterlace for x86/x86_64. Once this has merged, !55 will be adjusted to just hold a commit adding the SSE2 replacement code. I'm sure we'll find a way around the android build issue.