video-converter: add table based matrix8 implementation

video-converter: add table based matrix8 implementation

Based on patch from Mozzhuhin Andrey <nopscmn at gmail.com>

Add a table based matrix8 multiplication implementation. The algorithm
does not do any clipping so we need to make sure we never call this on
input that might need to be clipped. In general, this algorithm is
2 times faster than the orc optimized one and would be chosen for all
RGB -> YUV conversions and some YUV->YUV and RGB->RGB conversions.

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=732186