dt-bindings: iio: imu: st_lsm6dsx: add lsm6dso16is

Add device bindings for lsm6dso16is IMU sensor.
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/55b15b3e8453a12edcf8195ef9c9243a76f87096.1668605631.git.lorenzo@kernel.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/imu/st,lsm6dsx.yaml

@@ -33,6 +33,7 @@ properties:
           - st,lsm6dst
           - st,lsm6dsop
           - st,lsm6dsv
+          - st,lsm6dso16is
       - items:
           - const: st,asm330lhhx
           - const: st,lsm6dsr