powerpc/pseries: PAPR persistent memory support

This patch implements support for discovering storage class memory
devices at boot and for handling hotplug of new regions via RTAS
hotplug events.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
[mpe: Fix CONFIG_MEMORY_HOTPLUG=n build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/pseries/firmware.c

@@ -66,6 +66,7 @@ hypertas_fw_features_table[] = {
 	{FW_FEATURE_BEST_ENERGY,	"hcall-best-energy-1*"},
 	{FW_FEATURE_HPT_RESIZE,		"hcall-hpt-resize"},
 	{FW_FEATURE_BLOCK_REMOVE,	"hcall-block-remove"},
+	{FW_FEATURE_PAPR_SCM,		"hcall-scm"},
 };
 
 /* Build up the firmware features bitmask using the contents of