kernel/server_port: Make data members private

With this, all kernel objects finally have all of their data members
behind an interface, making it nicer to reason about interactions with
other code (as external code no longer has the freedom to totally alter
internals and potentially messing up invariants).

src/core/hle/service/sm/sm.h

@@ -67,7 +67,7 @@ public:
         if (port == nullptr) {
             return nullptr;
         }
-        return std::static_pointer_cast<T>(port->hle_handler);
+        return std::static_pointer_cast<T>(port->GetHLEHandler());
     }
 
     void InvokeControlRequest(Kernel::HLERequestContext& context);