INT 33 - MS MOUSE v7.0+ - ENUMERATE VIDEO MODES
        AX = 0029h
        CX = previous video mode
            0000h get first supported video mode
            other get next supported mode after mode CX
Return: CX = first/next video mode (0000h = no more video modes)
        BS:DX -> description of video mode or 0000h:0000h if none
Notes:  the enumerated video modes may be in any order and may repeat
        the description string (if available) is terminated by '$' followed by
          a NUL byte