topology/pre-process-object: update object config with attributes

topology/pre-process-object: update object config with attributes

Object attributes can be set in multiple places. Search for
the attribute value in the following order:
1. Value set in object instance
2. Default value set in the object's class definition
3. Inherited value from the parent object
4. Value set in the object instance embedded in the parent object
5. Value set in the object instance embedded in the parent class definition

Mandatory attributes must be found in one of the above, resulting
in an error if not found.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>