fix [3355413] Gyro calls onAccuracyChanged and reports accuracy as UNRELIABLE

- make sure to call onAccuracyChanged only when it actually changes
- only call onAccuracyChanged on Magnetic and Orientation sensors, which
  are the only ones to support it.
- for other sensors, call onAccuracyChanged only once with the
  SENSOR_STATUS_ACCURACY_HIGH value

Change-Id: Ic861e3d48d3b98dab74ffebe2746576f5b69f371