qcacmn: Separate pdev detach processing as per pdev attach

Separate out pdev detach processing as ol_txrx_pdev_detach()
and ol_txrx_pdev_pre_detach() corresponding to pdev attach
functions ol_txrx_pdev_attach() and ol_txrx_pdev_post_attach()
respectively.

Change-Id: I7fdbe70ad8262a57b61a742fcfb2779e323172af
CRs-Fixed: 2011937
2 files changed