Fix fail on get PostCode entry

Get url /redfish/v1/Systems/system/LogServices/PostCodes/Entries/<str>
return error.
Compare with sha dcf2ebc020257bc298d948fcb4da761c284e84d7
Condition checking is different from the original.

Tested:
Before fix:
curl -X GET http://${bmc}/redfish/v1/Systems/system/LogServices/PostCodes/Entries
...
{
      "@odata.id": "/redfish/v1/Systems/system/LogServices/PostCodes/Entries/B1-605",
      "@odata.type": "#LogEntry.v1_8_0.LogEntry",
      "Created": "1970-01-01T00:11:17+00:00",
      "EntryType": "Event",
      "Id": "B1-605",
      "Message": "Boot Count: 1; Time Stamp Offset: 603.1745 seconds; POST Code: 0x84",
      "MessageArgs": [
        "1",
        "603.1745",
        "0x84"
      ],
      "MessageId": "OpenBMC.0.2.BIOSPOSTCode",
      "Name": "POST Code Log Entry",
      "Severity": "OK"
    }
],
curl -X GET http://${bmc}/redfish/v1/Systems/system/LogServices/PostCodes/Entries/B1-605
{
  "error": {
    "@Message.ExtendedInfo": [
      {
        "@odata.type": "#Message.v1_1_1.Message",
        "Message": "The resource at the URI '/redfish/v1/Systems/system/LogServices/PostCodes/Entries/B1-605' was not found.",
        "MessageArgs": [
          "/redfish/v1/Systems/system/LogServices/PostCodes/Entries/B1-605"
        ],
        "MessageId": "Base.1.11.0.ResourceMissingAtURI",
        "MessageSeverity": "Critical",
        "Resolution": "Place a valid resource at the URI or correct the URI and resubmit the request."
      }
    ],
    "code": "Base.1.11.0.ResourceMissingAtURI",
    "message": "The resource at the URI '/redfish/v1/Systems/system/LogServices/PostCodes/Entries/B1-605' was not found."
  }

After fixed:
curl -X GET http://${bmc}/redfish/v1/Systems/system/LogServices/PostCodes/Entries/B1-605
{
  "@odata.id": "/redfish/v1/Systems/system/LogServices/PostCodes/Entries",
  "@odata.type": "#LogEntry.v1_4_0.LogEntry",
  "Description": "Collection of POST Code Log Entries",
  "Members": [
    {
      "@odata.id": "/redfish/v1/Systems/system/LogServices/PostCodes/Entries/B1-605",
      "@odata.type": "#LogEntry.v1_8_0.LogEntry",
      "Created": "1970-01-01T00:11:17+00:00",
      "EntryType": "Event",
      "Id": "B1-605",
      "Message": "Boot Count: 1; Time Stamp Offset: 603.1745 seconds; POST Code: 0x84",
      "MessageArgs": [
        "1",
        "603.1745",
        "0x84"
      ],
      "MessageId": "OpenBMC.0.2.BIOSPOSTCode",
      "Name": "POST Code Log Entry",
      "Severity": "OK"
    }
  ],

Signed-off-by: Tony Lee <tony.lee@quantatw.com>
Change-Id: Iada035214a9c1dc47be00c0ed3010562b80b0a3c
diff --git a/redfish-core/lib/log_services.hpp b/redfish-core/lib/log_services.hpp
index b69a8a5..82d53d9 100644
--- a/redfish-core/lib/log_services.hpp
+++ b/redfish-core/lib/log_services.hpp
@@ -3541,7 +3541,7 @@
     end = split[1].data() + split[1].size();
     auto [ptrValue, ecValue] = std::from_chars(start, end, currentValue);
 
-    return ptrValue == end && ecValue != std::errc();
+    return ptrValue == end && ecValue == std::errc();
 }
 
 inline void requestRoutesPostCodesEntryAdditionalData(App& app)