PCI: Prevent out of bounds access in numa_node override

Commit 12669631 ("PCI: Prevent out of bounds access in numa_node
override") missed that the user-provided node could also be negative.
Handle this case as well to avoid out-of-bounds accesses to the
node_states[] array.  However, allow the special value -1, i.e.
NUMA_NO_NODE, to be able to set the 'no specific node' configuration.

Fixes: 12669631 ("PCI: Prevent out of bounds access in numa_node override")
Fixes: 63692df1 ("PCI: Allow numa_node override via sysfs")
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Sasha Levin <sasha.levin@oracle.com>
CC: Prarit Bhargava <prarit@redhat.com>
CC: stable@vger.kernel.org	# v3.19+