INT 2F - MDEBUG display driver - INITIALIZE DRIVER
        AX = D001h
Return: CF set on error
        AL = driver semaphor
        AH = buffer semaphor
Notes:  MDEBUG calls this function after every succesful call of the function
          00h. The function should reset all internal data and the status of
          the driver. If this function returns an error, MDEBUG will not call
          the other functions in this popup session.
        MDEBUG can use any two consecutive multiplex numbers between C0h and
          FFh; the default is D0h for the display driver and D1h for the
          command driver