software node: read the reference args via the fwnode API

software node: read the reference args via the fwnode API

Once we allow software nodes to reference all kinds of firmware nodes,
the refnode here will no longer necessarily be a software node so read
its proprties going through its fwnode implementation.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>