Mark Page as Demand Paging Candidate

Notifies the DPMI host that a range of pages may be placed
at the head of the page-out candidate list, forcing these
pages to be replaced ahead of other pages even if the memory
has been accessed recently.  The contents of the pages will
be preserved.

Call With:

   AX     = 0702H
   BX:CX  = starting linear address of pages to mark as
           paging candidates
   SI:DI  = size of region to mark (bytes)

Returns:

   if function successful
   Carry flag= clear

   if function unsuccessful
   Carry flag= set
   AX     = error code
           8025H   invalid linear address (range
                   unallocated)

Notes:

o  This function does not force the pages to be swapped to
   disk immediately and should be treated as advisory only.
o  This function will always succeed on hosts that do not
   implement demand-paged virtual memory.
o  Partial pages will not be marked.
o  This function is useful, for example, if a client knows
   that a given piece of data will not be accessed for a
   long period of time.  That data is ideal for swapping to
   disk so that the physical memory it occupies can be used
   for other purposes.