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.cpp

@@ -0,0 +1,24 @@
+// Copyright 2018 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include "core/hle/service/am/idle.h"
+
+namespace Service::AM {
+
+IdleSys::IdleSys() : ServiceFramework{"idle:sys"} {
+    // clang-format off
+    static const FunctionInfo functions[] = {
+        {0, nullptr, "GetAutoPowerDownEvent"},
+        {1, nullptr, "Unknown1"},
+        {2, nullptr, "Unknown2"},
+        {3, nullptr, "Unknown3"},
+        {4, nullptr, "Unknown4"},
+        {5, nullptr, "Unknown5"},
+    };
+    // clang-format on
+
+    RegisterHandlers(functions);
+}
+
+} // namespace Service::AM