dt-bindings: iio: imu: st_lsm6dsx: introduce vdd-vddio regulators bindings

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/ae812b48528c48555a753c081acf1c9bb6376cc6.1605631305.git.lorenzo@kernel.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

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

@@ -42,6 +42,12 @@ properties:
 
   spi-max-frequency: true
 
+  vdd-supply:
+    description: if defined provides VDD power to the sensor.
+
+  vddio-supply:
+    description: if defined provides VDD IO power to the sensor.
+
   st,drdy-int-pin:
     $ref: '/schemas/types.yaml#/definitions/uint32'
     description: |