INT 13 - IBM/MS INT 13 Extensions - LOCK/UNLOCK DRIVE

	AH = 45h
	AL = operation
	    00h lock media in drive
	    01h unlock media
	    02h check lock status
	DL = drive number
Return: CF clear if successful
	    AH = 00h
	    AL = lock state (00h = unlocked)
	CF set on error
	    AH = error code (see #00234)
Notes:	this function is required to be supported for any removable drives
	  numbered 80h or higher
	a device may be locked even if no media is present in the drive
	up to 255 locks may be placed on a drive, and the media will not
	  be physically unlocked until all locks have been removed
SeeAlso: AH=41h"INT 13 Ext",AH=46h,AH=49h,INT 15/AH=52h"INT 13 Extensions"