i7core_edac: Probe on Xeons eariler

On the Xeon 55XX series cpus the pci deives are not exposed via acpi so
we much explicitly probe them to make the usable as a Linux PCI device.

This moves the detection of this state to before pci_register_driver is
called.  Its present position was not working on my systems, the driver
would complain about not finding a specific device.

This patch allows the driver to load on my systems.

Signed-off-by: Keith Mannthey <kmannth@us.ibm.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>