PEL: Remove P3 callout for Rainier system

Per updated Rainier system documentation, the P3 callout is no longer
needed.

Signed-off-by: Jim Wright <jlwright@us.ibm.com>
Change-Id: I1d4371903b1779be3a9f1340e0b1fc8f6fd27d95
diff --git a/extensions/openpower-pels/registry/message_registry.json b/extensions/openpower-pels/registry/message_registry.json
index 2efe0c9..23c7e38 100644
--- a/extensions/openpower-pels/registry/message_registry.json
+++ b/extensions/openpower-pels/registry/message_registry.json
@@ -2392,7 +2392,6 @@
                                 "CalloutList": [
                                     { "Priority": "medium", "LocCode": "P1" },
                                     { "Priority": "medium", "LocCode": "P2" },
-                                    { "Priority": "medium", "LocCode": "P3" },
                                     { "Priority": "low", "LocCode": "P0" }
                                 ]
                             }
@@ -2866,7 +2865,6 @@
                                 "CalloutList": [
                                     { "Priority": "medium", "LocCode": "P1" },
                                     { "Priority": "medium", "LocCode": "P2" },
-                                    { "Priority": "medium", "LocCode": "P3" },
                                     { "Priority": "low", "LocCode": "P0" }
                                 ]
                             }