qcacmn: Fix deleting unused timer in QCA6750 target

In QCA6750 target hif sleep timer is not used but timer
delete is performed during deinit path.

Fix this so that hif sleep timer delete operation is not
performed in QCA6750 target.

Change-Id: I54790f3b20af4f4b265ab37b593d300032f00fa5
CRs-Fixed: 3108047