IN  PIRP_CONTEXT IrpContext,
  IN  PCHAR BigEndian,
  IN  ULONG ByteCount,
  OUT PCHAR LittleEndian

Routine Description:

    This routine is called to convert a unicode string in big endian to
    little endian.  We start by copying all of the source bytes except
    the first.  This will put the low order bytes in the correct position.
    We then copy each high order byte in its correct position.


    BigEndian - Pointer to the string of big endian characters.

    ByteCount - Number of unicode characters in this string.

    LittleEndian - Pointer to array to store the little endian characters.

Return Value: