powerpc: Enable overlayfs on pseries and ppc64 defconfigs

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/configs/ppc64_defconfig b/arch/powerpc/configs/ppc64_defconfig
index 897869c..3315c9f 100644
--- a/arch/powerpc/configs/ppc64_defconfig
+++ b/arch/powerpc/configs/ppc64_defconfig
@@ -290,6 +290,7 @@
 CONFIG_NILFS2_FS=m
 CONFIG_AUTOFS4_FS=m
 CONFIG_FUSE_FS=m
+CONFIG_OVERLAY_FS=m
 CONFIG_ISO9660_FS=y
 CONFIG_UDF_FS=m
 CONFIG_MSDOS_FS=y