L3 update -- p9_pcie_config

  update owner comments
  address remaining todo items
  define constants to replace hardcoded bit definitions
  cleanup trace messages

Change-Id: Ibc075046d4494d3ec5bf85780ee58c919c6b68a2
CQ: HW363246
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/41116
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: Matt K. Light <mklight@us.ibm.com>
Reviewed-by: Joseph J. McGill <jmcgill@us.ibm.com>
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/41126
Reviewed-by: Hostboot Team <hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Sachin Gupta <sgupta2m@in.ibm.com>

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

@@ -2834,6 +2834,23 @@
     </chipEcFeature>
   </attribute>
 
+  <attribute>
+    <id>ATTR_CHIP_EC_FEATURE_HW363246</id>
+    <targetType>TARGET_TYPE_PROC_CHIP</targetType>
+    <description>
+      Nimbus DD1 only -- PCI Nest stack error report registers cannot be cleared
+    </description>
+    <chipEcFeature>
+      <chip>
+        <name>ENUM_ATTR_NAME_NIMBUS</name>
+        <ec>
+          <value>0x20</value>
+          <test>LESS_THAN</test>
+        </ec>
+      </chip>
+    </chipEcFeature>
+  </attribute>
+
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