sensor_board_armar7de: Torque Error Field no longer supported

The error field indicating whether a torque error has been detected is designed incorrectly and will be removed from future firmware versions of the sensor-actuator-pcb.

It must be removed from the devices driver.

Instead a counter sensor-field will be added which counts up every time an impossible jump between two torque adc values is recognized. This sensor-field is only used for debugging possible data corruption of the torque adc values.