Bump up version for openpower-pnor package

A backport of a fix in hostboot requires a bigger HBI partition so
moving up to a more recent level of the pnor package that includes
a bump.

Signed-off-by: Dan Crowell <dcrowell@us.ibm.com>
diff --git a/openpower/package/openpower-pnor/openpower-pnor.mk b/openpower/package/openpower-pnor/openpower-pnor.mk
index cba13e1..01fd3e9 100644
--- a/openpower/package/openpower-pnor/openpower-pnor.mk
+++ b/openpower/package/openpower-pnor/openpower-pnor.mk
@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-OPENPOWER_PNOR_VERSION ?= 2ea669b4aa574a9e0d121ca60e782b2354064eb0
+OPENPOWER_PNOR_VERSION ?= 4fbcc5ef382f0202fa3fc6c3451a64fc39af3588
 OPENPOWER_PNOR_SITE ?= $(call github,open-power,pnor,$(OPENPOWER_PNOR_VERSION))
 
 OPENPOWER_PNOR_LICENSE = Apache-2.0