INT 2F - Kingswood TSR Windows - POSITION CURSOR
        AX = 3901h
        BL = 07h
        CH = Y coordinate (0-10)
        CL = X coordinate (0-39)
Return: AX = error code (0000h if successful)
Note:   the hardware cursor is always disabled when a TSR window is opened;
          this call only sets a text position
SeeAlso: AX=3901h/BL=08h,AX=3901h/BL=09h