SubModel property under ComputerSystem Schema.

This commit implement changes to publish SubModel property
under ComputerSystem schema for BMCWeb.

Redfish validator has been executed on this change and no new
error was found.

Signed-off-by: Sunny Srivastava <sunnsr25@in.ibm.com>
Change-Id: Ibfb9d30c6be3b0aa8a327d6a5f906ce46a33d9f4
diff --git a/redfish-core/lib/systems.hpp b/redfish-core/lib/systems.hpp
index 80d3e05..944f730 100644
--- a/redfish-core/lib/systems.hpp
+++ b/redfish-core/lib/systems.hpp
@@ -539,7 +539,8 @@
                                         if ((propertyName == "PartNumber") ||
                                             (propertyName == "SerialNumber") ||
                                             (propertyName == "Manufacturer") ||
-                                            (propertyName == "Model"))
+                                            (propertyName == "Model") ||
+                                            (propertyName == "SubModel"))
                                         {
                                             const std::string* value =
                                                 std::get_if<std::string>(