linux-phytec-fsl

device property: keep single value inplace

We may save a lot of lines of code and space by keeping single values inside
the struct property_entry. Refactor the implementation to do so.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>