i2c: pca954x: Add reset GPIO support

If a reset GPIO support is specified, request the GPIO and get the chip
out of reset at probe time.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Documentation/devicetree/bindings/i2c/i2c-mux-pca954x.txt

@@ -13,6 +13,10 @@ Required Properties:
   - Standard I2C mux properties. See i2c-mux.txt in this directory.
   - I2C child bus nodes. See i2c-mux.txt in this directory.
 
+Optional Properties:
+
+  - reset-gpios: Reference to the GPIO connected to the reset input.
+
 
 Example: