Fix visibility of NET_INFO::SetParent

Without explictly inheriting the base SetParent method, the compiler was
warning a lot about hiding it due to the different argument type of the
new SetParent method.

pcbnew/netinfo.h

@@ -182,6 +182,10 @@ public:
         return 0.0;
     }
 
+protected:
+    // Hide base SetParent method to make the BOARD* method the prefered method for this class
+    using EDA_ITEM::SetParent;
+
 private:
     friend class NETINFO_LIST;