acpi, numa: fix pxm to online numa node associations

acpi, numa: fix pxm to online numa node associations

Commit 99759869faf1 "acpi: Add acpi_map_pxm_to_online_node()" added
support for mapping a given proximity to its nearest, by SLIT distance,
online node. However, it sometimes returns unexpected results due to the
fact that it switches from comparing the PXM node to the last node that
was closer than the current max.

    for_each_online_node(n) {
            dist = node_distance(node, n);
            if (dist < min_dist) {
                    min_dist = dist;
                    node = n;	<---- from this point we're using the
				      wrong node for node_distance()

Fixes: 99759869faf1 ("acpi: Add acpi_map_pxm_to_online_node()")
Cc: <stable@vger.kernel.org>
Reviewed-by: Toshi Kani <toshi.kani@hp.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>