libcamera: ipu3: cio2: Add a const sensor() method

Add a const version of the CIO2Device::sensor() method, that retrieves
a const pointer to the sensor_ class member, to be called by users
which only own a const reference to a CIO2Device class instance.

Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>

src/libcamera/pipeline/ipu3/cio2.h

@@ -50,6 +50,7 @@ public:
 	int stop();
 
 	CameraSensor *sensor() { return sensor_; }
+	const CameraSensor *sensor() const { return sensor_; }
 
 	int queueBuffer(Request *request, FrameBuffer *rawBuffer);
 	void tryReturnBuffer(FrameBuffer *buffer);