openpower: Default PNOR_SQUASHFS to n

Witherspoon is the only system that uses this option. Instead of
updating all of the non-Witherspoon systems to turn it off, this commit
defaults it to 'n' and updates the witherspoon defconfigs to enable it.

The change to zz is due to the new default.

Signed-off-by: Joel Stanley <joel@jms.id.au>
diff --git a/openpower/configs/witherspoon_dev_defconfig b/openpower/configs/witherspoon_dev_defconfig
index 34eeb58..2821a85 100644
--- a/openpower/configs/witherspoon_dev_defconfig
+++ b/openpower/configs/witherspoon_dev_defconfig
@@ -56,6 +56,7 @@
 BR2_IMA_CATALOG_FILENAME="ima_catalog.bin"
 BR2_OPENPOWER_TARGETING_BIN_FILENAME="WITHERSPOON_HB.targeting.bin"
 BR2_OPENPOWER_TARGETING_ECC_FILENAME="WITHERSPOON_HB.targeting.bin.ecc"
+BR2_BUILD_PNOR_SQUASHFS=y
 BR2_PACKAGE_PETITBOOT=y
 BR2_PACKAGE_PETITBOOT_MTD=y
 BR2_OCC_GPU_BIN_BUILD=y