PEL: Add message registry entry for power loss.

Add PEL message entry for power loss.

Tested:
Power on machine.
Build and install phosphor-log-manager and restart its service.
Delete all existing PEL entries.
Install patched message registry into /etc/phosphor-logging.
Use the  APC GUI for the ePDU to turn off power to all power supplies.
Turn power back on, get the PEL entry which shows the blackout entry.

Signed-off-by: Jay Meyer <jaymeyer@us.ibm.com>
Change-Id: Ic7b06c3db7d6356ac19dc46062ee8abc4f9c8723
diff --git a/extensions/openpower-pels/registry/schema/schema.json b/extensions/openpower-pels/registry/schema/schema.json
index a98f01c..330900a 100644
--- a/extensions/openpower-pels/registry/schema/schema.json
+++ b/extensions/openpower-pels/registry/schema/schema.json
@@ -438,7 +438,7 @@
         {
             "description": "The symbolic FRU callout.",
             "type": "string",
-            "enum": ["service_docs", "pwrsply", "air_mover", "pgood_part", "usb_pgood", "ambient_temp", "ambient_temp_back", "ambient_perf_loss"]
+            "enum": ["service_docs", "pwrsply", "air_mover", "pgood_part", "usb_pgood", "ambient_temp", "ambient_temp_back", "ambient_perf_loss", "ac_module"]
         },
 
         "symbolicFRUTrusted":