[PATCH] Make sure therm_adt746x only handles known hardware

This patch limits therm_adt746x to currently existing fan controllers in
Apple laptops.  It may avoid problems with future hardware.

Signed-off-by: Colin Leroy <colin@colino.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>