Make memory locking optional (mlock, VirtualLock).

Fix desired locking operation (to fix "sudo" memory).
It was discovered that some systems have outdated configuration.
With too tight limit, it's almost impossible to lock anything in memory.

rpcs3/util/vm_native.cpp

@@ -186,12 +186,12 @@ namespace utils
 #endif
 	}
 
-	void memory_lock(void* pointer, std::size_t size)
+	bool memory_lock(void* pointer, std::size_t size)
 	{
 #ifdef _WIN32
-		verify("VirtualLock" HERE), ::VirtualLock(pointer, size);
+		return ::VirtualLock(pointer, size);
 #else
-		verify("mlock" HERE), !::mlock(pointer, size);
+		return !::mlock(pointer, size);
 #endif
 	}