INT 6F - HP Vectra EX-BIOS - "F_IO_CTRL SF_ENABLE_SVC" - UNMASK 8041 SVC INT
	AX = 0400h
	BP = 001Eh (driver ID for V_S8259)
Return: AH = status (see #03744)
	BP,DS destroyed
SeeAlso: AH=00h"HP Vectra",AX=0402h"SF_DISABLE_SVC",AX=0404h"SF_ENABLE_KBD"
SeeAlso: AX=0408h"SF_ENABLE_HPHIL"