DOS Internal - Get/set volume descriptor preference

        Entry:
          AX = 150Eh
          BX = subfunction
            00h get preference
                DX = 0000h
                Return: DX = preference settings
            01h set preference
                DH = volume descriptor preference
                    01h = primary volume descriptor
                    02h = supplementary volume descriptor
                DL = supplementary volume descriptor preference
                    01h = shift-Kanji
          CX = drive number (0=A:)
        Return:
          CF set on error
            AX = error code (15=invalid drive,1=invalid function)