qcacmn: Add unregister API for direct buf ring

Add Unregister API to de-register and free resources in direct buf
module. Existing logic of freeing all resources as part of pdev destroy
does not take care of soc_start and soc_stop scenarios. Add this API to
enable modules to de-register as part of soc_stop and register during
start.

CRs-Fixed: 2385313
Change-Id: Ibe6f6bc5f4bd2acc5a9fe71eee09c151853073bc
8 files changed