Int 67 Fn DE05  - Virtual Control Program Interface - Free 4k Page         [E]

   AX = DE05h
   EDX = physical address of 4K page

Return: AH = 00h successful
   AH nonzero: failed

Note:  also available in protected mode by calling the protected-mode VCPI
     entry point

See Also: AH=3Fh,AX=DE04h