Avoid populating StaticNameServers property

Redfish ethernet schema has two properties for nameservers
1.NameServers - Represents nameservers currently in use on Interface
2.StaticNameServers -Represents only statically defined set of DNS

As we have only one DBUS property `Nameservers` which is used for both
the static and dynamic nameservers, So the idea behind this commit is
to not populate the StaticnameServers property when DHCP mode is
enabled.

Tested By:

GET https://${BMC_IP}/redfish/v1/Managers/bmc/EthernetInterfaces/eth0

Signed-off-by: Manojkiran Eda <manojkiran.eda@gmail.com>
Change-Id: I64f66bde55ec41dc78befbb659a0cbc425bbc24b
diff --git a/redfish-core/lib/ethernet.hpp b/redfish-core/lib/ethernet.hpp
index 7932210..17b953b 100644
--- a/redfish-core/lib/ethernet.hpp
+++ b/redfish-core/lib/ethernet.hpp
@@ -1539,7 +1539,15 @@
                               iface_id + "/VLANs"}};
 
         json_response["NameServers"] = ethData.nameservers;
-        json_response["StaticNameServers"] = ethData.nameservers;
+
+        if (!ethData.DHCPEnabled)
+        {
+            json_response["StaticNameServers"] = ethData.nameservers;
+        }
+        else
+        {
+            json_response["StaticNameServers"] = {};
+        }
 
         nlohmann::json &ipv4_array = json_response["IPv4Addresses"];
         ipv4_array = nlohmann::json::array();