ACPICA: Fix incorrect handling of PCI Express Root Bridge _HID

I could not get correct PCI Express bus number from the structure of
acpi_object_extra. I always get zero as bus number regardless of bus
location. I found that there is incorrect comparison with _HID (PNP0A08) in
acpi/events/evrgnini.c and PCI Express _BBN method always fail.
Therefore, we always get zero as PCI Express bus number.
http://bugzilla.kernel.org/show_bug.cgi?id=7145

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>