add SONY CXA2025AS YUV decoder present

[zack867]

According to page 17 of public SONY CXA2025AS Datasheet PDF.
It has a R-Y G-Y axis selector switch to switch axis angle for JAPAN NTSC-J and US NTSC-M
JP : R-Y: 95° * 0.78 G-Y: 240° * 0.3 B-Y: 0° * 1
US : R-Y: 112° * 0.83 G-Y: 252° * 0.3 B-Y: 0° * 1
Since nestopia already support native YUV decoder function,
I think it's a good idea to include SONY CXA2025AS-JP and SONY CXA2025AS-US present.

[carmiker]

I think it's a jolly good idea. I'm experimenting right now, and these numbers produce a nice palette in both cases. The US version is slightly different from the included SONY_CXA2025AS_US.pal. I suppose the YUV generator may be more accurate than this palette which I believe was handcrafted.