Ice Lake (Xeon Silver 4316): 2.01x faster (1147±36.8 vs. 571±38.2 decicycles) compared with avx2
This removes a dependency of checkasm on lavc/v210_dec.o and also allows to inline ff_v210dec_init() irrespectively of interposing. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>