service/am: Add missing am services

Adds the basic skeleton for missing am services idle:sys, omm, and spsm
based off the information provided by Switch Brew.

src/core/hle/service/am/idle.h

@@ -0,0 +1,16 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include "core/hle/service/service.h"
+
+namespace Service::AM {
+
+class IdleSys final : public ServiceFramework<IdleSys> {
+public:
+    explicit IdleSys();
+};
+
+} // namespace Service::AM