INT 6F - HP Vectra EX-BIOS - "F_GET_BYTE" - READ A BYTE OF DATA FROM DEVICE
	AH = 08h
	BP = driver ID (see #03741) for V_HPHIL (0114h), others
	---if device is V_HPHIL---
	BX = device address indicator (see #03760)
	DH = HP HIL device major address
	DL = HP-HIL device register (00h-7Fh)
Return: AH = status (see #03744)
	AL = value read from device
	BP,DS destroyed
Desc:	generic read-byte function; for driver V_HPHIL, retrieves the value
	  of a specific HP-HIL device register
Note:	this function is only available if the driver is in the open state
	  (see AX=020Eh"SF_OPEN")
SeeAlso: AH=06h"F_PUT_BYTE",AH=0Ah"F_PUT_BUFFER",AH=0Ch"F_GET_BUFFER"