INT 21 - DOS 5+ - IOCTL - QUERY GENERIC IOCTL CAPABILITY (HANDLE)
	AX = 4410h
	BX = handle for device
	CH = category code (see #01545)
	CL = function code (see #01546)
Return: CF clear if successful
	    AX = 0000h	specified IOCTL function is supported
	CF set on error
	    AL = 01h	IOCTL capability not available
Note:	a program which wishes to use Generic IOCTL calls beyond those in the
	  standard DOS 3.2 set may use this call first to see whether a
	  particular call is supported
SeeAlso: AX=440Ch,AX=440Dh"DOS 3.2+",AX=4411h