Static layout: Implement PNOR code update

Implement the PNOR code update by pflash tool in openpower-pnor-update
service, and update the related associations.

Tested: Verify PNOR code update succeeds.

Change-Id: I53781d6420071200ac2ed6837f7a79bf5e1162c2
Signed-off-by: Lei YU <mine260309@gmail.com>
diff --git a/openpower-pnor-update@.service b/openpower-pnor-update@.service
new file mode 100644
index 0000000..b1db219
--- /dev/null
+++ b/openpower-pnor-update@.service
@@ -0,0 +1,9 @@
+[Unit]
+Description=Update PNOR %I
+
+[Service]
+Type=oneshot
+RemainAfterExit=no
+ExecStart=/usr/sbin/pflash -E -f -p %I
+SyslogIdentifier=pflash
+