topology: pre-processor: Add support for enum controls

alsa-project/alsa-utils pull request #236 was opened from ranj063:

Add support for adding enum controls in the topology pre-processor.

Request URL : https://github.com/alsa-project/alsa-utils/pull/236 Patch URL : https://github.com/alsa-project/alsa-utils/pull/236.patch Repository URL: https://github.com/alsa-project/alsa-utils