dt-bindings: iio: imu: st_lsm6dsx: add lsm6dst device bindings

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/05e4273f2544230049b2cd82c6bf1be788a8e483.1601985763.git.lorenzo@kernel.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/imu/st_lsm6dsx.txt

@@ -16,6 +16,7 @@ Required properties:
   "st,lsm9ds1-imu"
   "st,lsm6ds0"
   "st,lsm6dsrx"
+  "st,lsm6dst"
 - reg: i2c address of the sensor / spi cs line
 
 Optional properties: