add motor_poles to BBL header (#932)

* add motor_poles to BBL header

Author: nerdCopter

src/main/blackbox/blackbox.c

@@ -1267,6 +1267,7 @@ static bool blackboxWriteSysinfo(void) {
         BLACKBOX_PRINT_HEADER_LINE("motor_pwm_protocol", "%d",              motorConfig()->dev.motorPwmProtocol);
         BLACKBOX_PRINT_HEADER_LINE("motor_pwm_rate", "%d",                  motorConfig()->dev.motorPwmRate);
         BLACKBOX_PRINT_HEADER_LINE("dshot_idle_value", "%d",                motorConfig()->digitalIdleOffsetValue);
+        BLACKBOX_PRINT_HEADER_LINE("motor_poles", "%d",                     motorConfig()->motorPoleCount);
         BLACKBOX_PRINT_HEADER_LINE("debug_mode", "%d",                      systemConfig()->debug_mode);
         BLACKBOX_PRINT_HEADER_LINE("features", "%d",                        featureConfig()->enabledFeatures);
 #ifdef USE_RC_SMOOTHING_FILTER