Missing support for Cirrus 4 bpp modes

[Vort]

When Windows 3.11 CL-GD5446 driver tries switching to 800x600x4 or 1024x768x4 modes, switch to 640x480x4 happens instead.

It happens because Cirrus modes 0x58 and 0x5D are missing from BIOS tables.
With vgatables.h hacked this way, driver is able to switch to 800x600x4 mode successfully, but such solution is of course incorrect - proper implementation is needed.

diff --git a/vgabios/vgatables.h b/vgabios/vgatables.h
index ff6e7a8..adea6d9 100644
--- a/vgabios/vgatables.h
+++ b/vgabios/vgatables.h
@@ -85,7 +85,7 @@
  * Tables of default values for each mode
  *
  */
-#define MODE_MAX   15
+#define MODE_MAX   16
 #define TEXT       0x00
 #define GRAPH      0x01
 
@@ -129,6 +129,7 @@ static VGAMODES vga_modes[MODE_MAX+1]=
  {0x11, GRAPH, PLANAR1, 1, 0xA000, 0x02, 0x1a},
  {0x12, GRAPH, PLANAR4, 4, 0xA000, 0x02, 0x1b},
  {0x13, GRAPH, LINEAR8, 8, 0xA000, 0x03, 0x1c},
+ {0x58, GRAPH, PLANAR4, 4, 0xA000, 0x02, 0x1d},
  {0x6A, GRAPH, PLANAR4, 4, 0xA000, 0x02, 0x1d}
 };

Besides Windows 3.11, VBETest shows lack of these modes as well:

With cl-gd5446_pci_vga_bios_version_1.31.u2, these modes are in place:

Version: 85c58ff