Debug:Qutex: Add deadlock detection based on elapsed time

We now detect that a deadlock is likely when
CONFIG_DEBUG_QUTEX_DEADLOCK_TIMEOUT_MS has elapsed. This is the
preliminary work required to do a backtrace through the call
stack and figure out if a deadlock has really occured.

To do this, we'd have to go through the async call chain and
search for a previous caller which acquired the same qutex as
the one that first failed during this Lockvoker LockSet acquisition
attempt.

include/qutex.h

@@ -24,8 +24,8 @@ public:
 	/**
 	 * @brief Constructor
 	 */
-	Qutex()
-	: isOwned(false)
+	Qutex(const std::string &_name)
+	: isOwned(false), name(_name)
 	{}
 
 	/**
@@ -88,6 +88,7 @@ public:
 	SpinLock lock;
 	LockerAndInvokerBase::List queue;
 	bool isOwned;
+	std::string name;
 };
 
 } // namespace smo