PCI: rpaphp: change device tree examination

Change the criterion that RPA PCI Hotplug and RPA DLPAR use when
determining the hotplug capabilities of a given device node.  The
"device_type" property is less consistent than "name" across PCI nodes
on newer hardware.

Signed-off-by: John Rose <johnrose@austin.ibm.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>