INT 2F - NETWORK REDIRECTOR (DOS 3.x only) - UNLOCK REGION OF FILE

	AX = 110Bh
	BX = file handle
	CX:DX = starting offset
	SI = high word of size
	STACK: WORD low word of size
	ES:DI -> SFT for file
	    SFT DPB field -> DPB of drive containing file
Return: CF set on error
	   AL = DOS error code (see #01680 at INT 21/AH=59h/BX=0000h)
	STACK unchanged
Note:	this function is called by the DOS 3.1-3.31 kernel; DOS 4.0+ calls
	  AX=110Ah instead
SeeAlso: AX=110Ah,INT 21/AH=5Ch