Copter: use new scheduler API

ArduCopter/failsafe.pde

@@ -31,8 +31,10 @@ void failsafe_disable()
 //
 //  failsafe_check - this function is called from the core timer interrupt at 1kHz.
 //
-void failsafe_check(uint32_t tnow)
+void failsafe_check(void *arg)
 {
+    uint32_t tnow = hal.scheduler->micros();
+
     if (mainLoop_count != failsafe_last_mainLoop_count) {
         // the main loop is running, all is OK
         failsafe_last_mainLoop_count = mainLoop_count;
@@ -56,4 +58,4 @@ void failsafe_check(uint32_t tnow)
             motors.output();
         }
     }
-}
+}