APMrover2: fix wrong printf format for 32 bits

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

APMrover2/test.cpp

@@ -401,7 +401,7 @@ int8_t Rover::test_mag(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, (double)mag.z,
                                     (double)mag_ofs.x, (double)mag_ofs.y, (double)mag_ofs.z);