ACPI: dock: Fix symbol conflict between acpiphp and dock

Fix bug which will cause acpiphp to not be able to load when dock.ko
cannot load.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>