INT 21 - Phar Lap 386/DOS-Extender VMM - LIMIT PROGRAM'S EXTENDED MEM USAGE

	AX = 2521h
	EBX = max 4k pages of physical extended memory which program may use
Return: CF clear if successful
	   EBX = maximum limit in pages
	   ECX = minimum limit in pages
	CF set on error
	    EAX = error code
		08h insufficient memory or -nopage switch used
SeeAlso: AX=2522h