feat(MCOL-6082): Multiple readers of dbroots using OamCache logic

This patch introduces centralized logic of selecting what dbroot is
accessible in PrimProc on what node. The logic is in OamCache for time
being and can be moved later.

oam/oamcpp/liboamcpp.cpp

@@ -684,12 +684,14 @@ void Oam::getPmDbrootConfig(const int pmid, DBRootConfigList& dbrootconfiglist)
  * Get DBRoot - PM Config data
  *
  ********************************************************************/
-void Oam::getDbrootPmConfig(const int dbrootid, int& pmid)
+void Oam::getDbrootPmConfig(const int dbrootid, set<int>& pmids)
 {
   SystemModuleTypeConfig systemmoduletypeconfig;
   ModuleTypeConfig moduletypeconfig;
   ModuleConfig moduleconfig;
 
+  pmids.clear();
+
   try
   {
     getSystemConfig(systemmoduletypeconfig);
@@ -716,13 +718,16 @@ void Oam::getDbrootPmConfig(const int dbrootid, int& pmid)
           {
             if (*pt1 == dbrootid)
             {
-              pmid = (*pt).DeviceID;
-              return;
+              pmids.insert((*pt).DeviceID);
             }
           }
         }
       }
     }
+    if (!pmids.empty())
+    {
+      return;
+    }
 
     // dbrootid not found, return with error
     exceptionControl("getDbrootPmConfig", API_INVALID_PARAMETER);