software node: remove property_entry_read_uNN_array functions

There is absolutely no reason to have them as we can handle it all nicely in
property_entry_read_int_array().

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>