This patch changes the way devices are searched by using product id instead of
device/function numbers. Tested in a Sandy Bridge and a Ivy Bridge machine to
make sure everything works properly.

Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: NAristeu Rozanski <aris@redhat.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>