INT 10 - SOLLEX SuperVGA - MULTIPLE FONT CONTROL
        AX = 7F06h
        BL = subfunction
            00h set multiple font state
                CX = new state (00h off, 01h on)
            01h get multiple font state
                Return: BL = current state (00h off, 01h on)
Return: AL != 7Fh if not supported
        AL = 7Fh if supported
            AH = status
                00h successful
                01h failed