ArduCopter: fix wrong printf format for 32 bits

Heading is a 32 bits value, so use %u.

ArduCopter/test.cpp

@@ -118,7 +118,7 @@ int8_t Copter::test_compass(uint8_t argc, const Menu::arg *argv)
                 if (compass.healthy()) {
                     const Vector3f &mag_ofs = compass.get_offsets();
                     const Vector3f &mag = compass.get_field();
-                    cliSerial->printf("Heading: %ld, XYZ: %.0f, %.0f, %.0f,\tXYZoff: %6.2f, %6.2f, %6.2f\n",
+                    cliSerial->printf("Heading: %d, XYZ: %.0f, %.0f, %.0f,\tXYZoff: %6.2f, %6.2f, %6.2f\n",
                                         (wrap_360_cd(ToDeg(heading) * 100)) /100,
                                         (double)mag.x,
                                         (double)mag.y,