INT 31 P - DPMIsee DOS Protected-Mode Interface 0.9+ - UNLOCK LINEAR REGION
	AX = 0601h
	BX:CX = starting linear address
	SI:DI = size of region in bytes
Return: CF clear if successful
	CF set on error
	    none of the memory is unlocked
	    AX = error code (DPMIsee DOS Protected-Mode Interface 1.0+) (8002h,8025h) (see #03143)
Notes:	pages at beginning and end will be unlocked if the region overlaps them
	memory whose lock count has not reached zero remains locked
SeeAlso: AX=0005h,AX=0600h,INT 21/AX=251Bh,INT 21/AX=EB07h