powerpc/eeh: I/O chip next error

The patch implements the backend for EEH core to retrieve next
EEH error to handle. For the informational errors, we won't bother
the EEH core. Otherwise, the EEH should take appropriate actions
depending on the return value:

	0 - No further errors detected
	1 - Frozen PE
	2 - Fenced PHB
	3 - Dead PHB
	4 - Dead IOC
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powernv/pci.h

@@ -93,6 +93,7 @@ struct pnv_phb {
 #ifdef CONFIG_EEH
 	struct pnv_eeh_ops	*eeh_ops;
 	int			eeh_enabled;
+	int			removed;
 #endif
 
 #ifdef CONFIG_PCI_MSI