fix [1847499] sensors.h : "roll" documentation is wrong
diff --git a/include/hardware/sensors.h b/include/hardware/sensors.h
index 094b3ee..db7d263 100644
--- a/include/hardware/sensors.h
+++ b/include/hardware/sensors.h
@@ -137,7 +137,7 @@
  *  the z-axis moves toward the y-axis.
  *
  * roll: Rotation around Y axis (-90<=roll<=90), with positive values when
- *  the z-axis moves AWAY from the x-axis.
+ *  the x-axis moves AWAY from the z-axis.
  * 
  * Note: This definition is different from yaw, pitch and roll used in aviation
  *  where the X axis is along the long side of the plane (tail to nose).