INT 2F - DOS 3.3+ internal - GET DEVICE CHAIN

	AX = 122Ch
Return: BX:AX -> header of second device driver (NUL is first) in driver chain
Note:	although this function exists in DR DOS 5.0 and Novell DOS 7, it
	  always returns 0000h:0000h prior to Novell DOS 7 Update 15
SeeAlso: INT 21/AH=52h