powerpc/pseries: Read common partition via pstore

This patch exploits pstore subsystem to read details of common partition
in NVRAM to a separate file in /dev/pstore. For instance, common partition
details will be stored in a file named [common-nvram-6].

Signed-off-by: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Reviewed-by: Jim Keniston <jkenisto@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index 615dc18..656699f 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -38,6 +38,7 @@
 	/* PPC64 partition types */
 	PSTORE_TYPE_PPC_RTAS	= 4,
 	PSTORE_TYPE_PPC_OF	= 5,
+	PSTORE_TYPE_PPC_COMMON	= 6,
 	PSTORE_TYPE_UNKNOWN	= 255
 };