service: Reduce header include overhead

src/core/hle/service/sockets/sockets.h

@@ -4,13 +4,17 @@
 
 #pragma once
 
+#include "common/common_funcs.h"
 #include "common/common_types.h"
-#include "core/hle/service/service.h"
 
 namespace Core {
 class System;
 }
 
+namespace Service::SM {
+class ServiceManager;
+}
+
 namespace Service::Sockets {
 
 enum class Errno : u32 {