tta/x86: add ff_ttafilter_process_dec_{ssse3, sse4}

Results are from a Win64 build running on an AMD FX 6300

1121 decicycles in ttafilter_process_dec_c, 16777112 runs, 104 skips
522 decicycles in ff_ttafilter_process_dec_ssse3, 16777149 runs, 67 skips
477 decicycles in ff_ttafilter_process_dec_sse4, 16777156 runs, 60 skips

Signed-off-by: James Almer <jamrial@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>