Dead code in spectrum telemetry

[error414]

https://github.com/iNavFlight/inav/blob/master/src/main/telemetry/srxl.c#L187

Inav does not contain USE_ESC_SENSOR_TELEMETRY neither USE_DSHOT_TELEMETRY, neither getEscSensorData(ESC_SENSOR_COMBINED); Probably acidently compied from betaflight, https://github.com/betaflight/betaflight/blob/master/src/main/sensors/esc_sensor.c#L155

If nobody complained about it probably we can remove it, or fix it, unfortunately I don't have any spectrum device.

uint16_t getMotorAveragePeriod(void)
{

#if defined( USE_ESC_SENSOR_TELEMETRY) || defined( USE_DSHOT_TELEMETRY)
    uint32_t rpm = 0;
    uint16_t period_us = SPEKTRUM_RPM_UNUSED;

#if defined( USE_ESC_SENSOR_TELEMETRY)
    escSensorData_t *escData = getEscSensorData(ESC_SENSOR_COMBINED);
    if (escData != NULL) {
        rpm = escData->rpm;
    }
#endif

#if defined(USE_DSHOT_TELEMETRY)
    if (useDshotTelemetry) {
        uint16_t motors = getMotorCount();

        if (motors > 0) {
            for (int motor = 0; motor < motors; motor++) {
                rpm += getDshotTelemetry(motor);
            }
            rpm = 100.0f / (motorConfig()->motorPoleCount / 2.0f) * rpm;  // convert erpm freq to RPM.
            rpm /= motors;           // Average combined rpm
        }
    }
#endif

    if (rpm > SPEKTRUM_MIN_RPM && rpm < SPEKTRUM_MAX_RPM) {
        period_us = MICROSEC_PER_MINUTE / rpm; // revs/minute -> microSeconds
    } else {
        period_us = MICROSEC_PER_MINUTE / SPEKTRUM_MIN_RPM;
    }

    return period_us;
#else
    return SPEKTRUM_RPM_UNUSED;
#endif
}
`

[sensei-hacker]

Note to self - put this code back if you end up doing that thing, Sensei.
But it's friggin Spektrum, so whatever.