libcamera: controls: Merge ControlInfoMap and V4L2ControlInfoMap

The ControlInfoMap and V4L2ControlInfoMap classes are very similar, with
the latter adding convenience accessors based on numerical IDs for the
former, as well as a cached idmap. Both features can be useful for
ControlInfoMap in the context of serialisation, and merging the two
classes will further simplify the IPA API.

Import all the features of V4L2ControlInfoMap into ControlInfoMap,
turning the latter into a real class. A few new constructors and
assignment operators are added for completeness.

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

src/libcamera/camera_sensor.cpp

@@ -251,7 +251,7 @@ int CameraSensor::setFormat(V4L2SubdeviceFormat *format)
  * \brief Retrieve the supported V4L2 controls and their information
  * \return A map of the V4L2 controls supported by the sensor
  */
-const V4L2ControlInfoMap &CameraSensor::controls() const
+const ControlInfoMap &CameraSensor::controls() const
 {
 	return subdev_->controls();
 }