device property: Remove struct property_set

Replacing struct property_set with the software nodes that
were just introduced.

The API and functionality for adding properties to devices
remains the same, however, the goal is to convert the
drivers to use the API for software nodes when the device
has no real firmware node, and use the old API only when
"extra" build-in properties are needed.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>