[Patch] OAK Oti-037 VGA

[EluanCM]

While the Oti-037 has fewer capabilities than the already emulated Oti-067, its BIOS is somewhat pickier and did some tests that PCem didn't pass yet with the Oti-067 code, including enabling/disabling the controller, color diagnostic reading and reading from undocumented registers.
The diagnostic test using the Color Plane Enable and the Input Status Register required some changes to this code in PCem, which used a heuristic previously. Now the information is copied from the Overscan Color Register, which, while technically more correct, may break other VGAs because I don't have BIOSes for every card that PCem emulates to test.
Also perhaps some things like the VGA Enable register should be moved to the generic vid_svga.c.

This is the last component needed to emulate my old Hyundai SUPER-286TR (Award 286 Clone/SCAT Chipset/12.5mhz, 1MB RAM, Oak Oti-037)

[SarahWalker]

Committed at rev 1065.