Clockgate disable workaround for HW452921

Change-Id: I09ec35894a488f0c9e2b03d8726b3a5a3ce08fcf
CQ: HW452921
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/62413
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: PPE CI <ppe-ci+hostboot@us.ibm.com>
Tested-by: Hostboot CI <hostboot-ci+hostboot@us.ibm.com>
Reviewed-by: Jennifer A. Stofer <stofer@us.ibm.com>
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/62430
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP HW <op-hw-jenkins+hostboot@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>

src/import/chips/p9/procedures/xml/attribute_info/chip_ec_attributes.xml

@@ -557,16 +557,16 @@
   </attribute>
   <!-- ********************************************************************* -->
   <attribute>
-    <id>ATTR_CHIP_EC_FEATURE_HW434484</id>
+    <id>ATTR_CHIP_EC_FEATURE_HW434484_HW452921</id>
     <targetType>TARGET_TYPE_PROC_CHIP, TARGET_TYPE_PROC_CHIP</targetType>
     <description>
-      HW434484 - ISU clockgate
+      HW434484 / HW452921 - ISU clockgate
     </description>
     <chipEcFeature>
       <chip>
         <name>ENUM_ATTR_NAME_NIMBUS</name>
         <ec>
-          <value>0x23</value>
+          <value>0x20</value>
           <test>GREATER_THAN_OR_EQUAL</test>
         </ec>
       </chip>