minor build fixes and ignored warnings for GCC 9 (#14159)

- px4io task_main_trampoline add return
 - iridiumsbd main_loop_helper add return
 - drivers/uavcan ignore Wcast-align, Wdeprecated-copy, and Waddress-of-packed-member for now
 - flashparams ignore Wvla-larger-than
 - test_time fix printf type

src/drivers/telemetry/iridiumsbd/IridiumSBD.cpp

@@ -213,7 +213,7 @@ int IridiumSBD::ioctl(struct file *filp, int cmd, unsigned long arg)
 // private functions                                                 //
 ///////////////////////////////////////////////////////////////////////
 
-void IridiumSBD::main_loop_helper(int argc, char *argv[])
+int IridiumSBD::main_loop_helper(int argc, char *argv[])
 {
 	// start the main loop and stay in it
 	IridiumSBD::instance->main_loop(argc, argv);
@@ -225,6 +225,7 @@ void IridiumSBD::main_loop_helper(int argc, char *argv[])
 	IridiumSBD::instance = nullptr;
 
 	PX4_WARN("stopped");
+	return 0;
 }
 
 void IridiumSBD::main_loop(int argc, char *argv[])

src/drivers/telemetry/iridiumsbd/IridiumSBD.h

@@ -139,7 +139,7 @@ private:
 	/*
 	 * Entry point of the task, has to be a static function
 	 */
-	static void main_loop_helper(int argc, char *argv[]);
+	static int main_loop_helper(int argc, char *argv[]);
 
 	/*
 	 * Main driver loop