amd64_edac: enforce synchronous probe

While testing asynchronous PCI probe on this driver I noticed it failed
because the driver checks if any of the PCI devices have been bound to
the driver after registering it, which obviously does not work if
probing is asynchronous.

While there are patches and discussions on how the driver should behave
are ongoing, let's enforce synchronous probe for this driver for now.

Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>