LogServices: Fix dump timestamp regression

https://gerrit.openbmc.org/c/openbmc/bmcweb/+/55468 was a refactoring
task that was not intended to have any client impact. However it had a
bug where it unintentionally changed the “Created” timestamp of log
entries of all dump types to be smaller (earlier) than pre-refactoring.

Tested:

FaultLog entry before fix (timestamp too large--reported as max Redfish
time):
curl k -H "X-Auth-Token: $token" -X GET http://${bmc}/redfish/v1/Managers/bmc/LogServices/FaultLog/Entries/1
{
  "@odata.id": "/redfish/v1/Managers/bmc/LogServices/FaultLog/Entries/1",
  "@odata.type": "#LogEntry.v1_8_0.LogEntry",
  "Created": "9999-12-31T23:59:59+00:00",
  "EntryType": "Event",
  "Id": "1",
  "Name": "FaultLog Dump Entry"
}

FaultLog entry after fix (timestamp reported correctly):
curl -k -H "X-Auth-Token: $token" -X GET http://${bmc}/redfish/v1/Managers/bmc/LogServices/FaultLog/Entries/1
{
  "@odata.id": "/redfish/v1/Managers/bmc/LogServices/FaultLog/Entries/1",
  "@odata.type": "#LogEntry.v1_8_0.LogEntry",
  "Created": "2022-08-14T10:29:40+00:00",
  "EntryType": "Event",
  "Id": "1",
  "Name": "FaultLog Dump Entry"
}

Tested similarly for a BMC Dump entry.

Interestingly, it seems like the System Dump entry timestamp before the
refactoring task was too small, and the bug actually helped to correct
it. In any case, this change reverts timestamp behavior to match what it
was pre-refactoring.

Redfish Service Validator succeeded on the following URI trees:
/redfish/v1/Managers/bmc/LogServices/FaultLog
/redfish/v1/Managers/bmc/LogServices/Dump
/redfish/v1/Systems/system/LogServices/Dump

Signed-off-by: Claire Weinan <cweinan@google.com>
Change-Id: I7badbd348595a7bcb61982a4cd6b7e82a16b0219
diff --git a/redfish-core/lib/log_services.hpp b/redfish-core/lib/log_services.hpp
index 32afd36..8c062aa 100644
--- a/redfish-core/lib/log_services.hpp
+++ b/redfish-core/lib/log_services.hpp
@@ -384,7 +384,7 @@
                         messages::internalError(asyncResp->res);
                         break;
                     }
-                    timestamp = *usecsTimeStamp;
+                    timestamp = (*usecsTimeStamp / 1000 / 1000);
                     break;
                 }
             }