PEL: Add SBE code maintenance procedure

Maintenance procedures are part of the PEL callout section.  This
procedure is used to indicate the problem is due to code (a bug)
SBE image.

Signed-off-by: Jayanth Othayoth <ojayanth@in.ibm.com>
Change-Id: I8e1a04b2c8aa83c178990331f181ed026ac62db9
diff --git a/extensions/openpower-pels/registry/schema/schema.json b/extensions/openpower-pels/registry/schema/schema.json
index 64b0ade..b0539c3 100644
--- a/extensions/openpower-pels/registry/schema/schema.json
+++ b/extensions/openpower-pels/registry/schema/schema.json
@@ -451,7 +451,7 @@
         {
             "description": "The maintenance procedure callout.",
             "type": "string",
-            "enum": ["bmc_code", "next_level_support"]
+            "enum": ["bmc_code", "next_level_support", "sbe_code"]
         },
 
         "useInventoryLocCode":