INT 21 - STARLITE architecture - UNMAP DRIVE LETTER                             
	AX = 5F06h
	DL = drive to be unmapped (0=A:)
Return: CF set on error
	    AX = error code (see #01680 at AH=59h/BX=0000h)
	CF clear if successful
SeeAlso: AX=5F05h"STARLITE",INT 60/AX=0003h