acpi/hmat: Register performance attributes

Save the best performance access attributes and register these with the
memory's node if HMAT provides the locality table. While HMAT does make
it possible to know performance for all possible initiator-target
pairings, we export only the local pairings at this time.

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Tested-by: Brice Goglin <Brice.Goglin@inria.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>