refactor(sensors): ec11 rotation sensor value in degrees.

* Add new `steps` property to the `aips,ec11` binding, to make
  the driver properly report degrees in the rotation delta channel.
* Handle old sensor values in sensor rotate behavior.

app/drivers/sensor/ec11/ec11.h

@@ -14,6 +14,7 @@ struct ec11_config {
     const struct gpio_dt_spec a;
     const struct gpio_dt_spec b;
 
+    const uint16_t steps;
     const uint8_t resolution;
 };