PCI: pci-label: Fix build failure when CONFIG_NLS is set to 'm' by allmodconfig

Create a kconfig option symbol for PCI_LABEL and enable it
when DMI || ACPI are enabled.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>