powerpc/eeh: PowerNV EEH backends

The patch adds EEH backends for PowerNV platform. It's notable that
part of those EEH backends call to the I/O chip dependent backends.

[Removed pointless change to eeh_pseries.c -- BenH]
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powernv/Makefile

@@ -3,4 +3,4 @@ obj-y			+= opal-rtc.o opal-nvram.o
 
 obj-$(CONFIG_SMP)	+= smp.o
 obj-$(CONFIG_PCI)	+= pci.o pci-p5ioc2.o pci-ioda.o
-obj-$(CONFIG_EEH)	+= eeh-ioda.o
+obj-$(CONFIG_EEH)	+= eeh-ioda.o eeh-powernv.o