powerpc/pseries: Enable PSTORE in pseries_defconfig

Since now we have pstore support for nvram in pseries, enable it
in the default config. With this config option enabled, pstore
infra-structure will be used to read/write the messages from/to nvram.
Signed-off-by: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/configs/pseries_defconfig

@@ -296,6 +296,7 @@ CONFIG_SQUASHFS=m
 CONFIG_SQUASHFS_XATTR=y
 CONFIG_SQUASHFS_LZO=y
 CONFIG_SQUASHFS_XZ=y
+CONFIG_PSTORE=y
 CONFIG_NFS_FS=y
 CONFIG_NFS_V3_ACL=y
 CONFIG_NFS_V4=y