HTMGT: Disable DIMM thermal monitoring

Temporarily disable DIMM thermal monitoring by the OCC while
defect is being investigated.

Change-Id: Iee8465022f486e1e4f17e6ea057e3b3e3f0b86ee
CQ: SW393253
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/42383
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Reviewed-by: Martha Broyles <mbroyles@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Sheldon R. Bailey <baileysh@us.ibm.com>
Reviewed-by: Daniel M. Crowell <dcrowell@us.ibm.com>

src/usr/targeting/common/xmltohb/attribute_types_openpower.xml

@@ -908,10 +908,10 @@ ID for the sensor number returned with the elog. -->
     </description>
     <simpleType>
         <uint32_t>
-            <default>0</default>
+            <default>0x00000800</default> <!-- FLAG_DISABLE_MEM_CONFIG -->
         </uint32_t>
     </simpleType>
-    <persistency>volatile-zeroed</persistency>
+    <persistency>volatile</persistency>
     <readable/>
     <writeable/>
 </attribute>