PEL: Get rid of the enum for a maint procedure

It simplifies the code to just use the string name of the procedure as defined
by the message registry schema, and make it be less maintenance to add
new procedures in the future, especially if they come from the registry
so the enum isn't even needed.

This will also make it the same as upcoming support for symbolic FRU
callouts, which will always just come from the registry or an external
user so would not need an enum.

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: Ia8550235678ba1fc717a6b0875e2d7ff3888bfec
diff --git a/extensions/openpower-pels/fru_identity.hpp b/extensions/openpower-pels/fru_identity.hpp
index 016f3fd..669dc01 100644
--- a/extensions/openpower-pels/fru_identity.hpp
+++ b/extensions/openpower-pels/fru_identity.hpp
@@ -89,9 +89,10 @@
      *
      * Creates the object with a maintenance procedure callout.
      *
-     * @param[in] procedure - The procedure to use
+     * @param[in] procedureFromRegistry - The maintenance procedure name
+     *                                    as defined in the message registry.
      */
-    FRUIdentity(MaintProcedure procedure);
+    FRUIdentity(const std::string& procedureFromRegistry);
 
     /**
      * @brief Flatten the object into the stream
@@ -230,8 +231,11 @@
      * @brief Sets the 8 character null terminated procedure
      *        field.  This is in the same field as the part
      *        number since they are mutually exclusive.
+     *
+     * @param procedureFromRegistry - The procedure name as defined in
+     *                                the PEL message registry.
      */
-    void setMaintenanceProcedure(MaintProcedure procedure);
+    void setMaintenanceProcedure(const std::string& procedureFromRegistry);
 
     /**
      * @brief The callout substructure type field. Will be "ID".