HLE: Use std::chrono::nanoseconds instead of a plain u64 in SleepClientThread.

src/core/hle/kernel/hle_ipc.h

@@ -5,6 +5,7 @@
 #pragma once
 
 #include <array>
+#include <chrono>
 #include <memory>
 #include <string>
 #include <vector>
@@ -146,7 +147,7 @@ public:
     using WakeupCallback = std::function<void(SharedPtr<Thread> thread, HLERequestContext& context,
                                               ThreadWakeupReason reason)>;
 
-    /*
+    /**
      * Puts the specified guest thread to sleep until the returned event is signaled or until the
      * specified timeout expires.
      * @param thread Thread to be put to sleep.
@@ -159,7 +160,7 @@ public:
      * @returns Event that when signaled will resume the thread and call the callback function.
      */
     SharedPtr<Event> SleepClientThread(SharedPtr<Thread> thread, const std::string& reason,
-                                       u64 timeout, WakeupCallback&& callback);
+                                       std::chrono::nanoseconds timeout, WakeupCallback&& callback);
 
     /**
      * Resolves a object id from the request command buffer into a pointer to an object. See the