qcacmn: Use DEFERRABLE_WORK instead of DELAYED_WORK for BUS BW

For static display case, BUS BW work periodically wakes up the
APPS because bus bw work is created as DELAYED_WORK.
This has the power impact in case of static display.

Use DEFERRABLE_WORK instead of DELAYED_WORK for bus bw work.
DEFERRABLE_WORK won't wake up the APPS periodically in static
display case.

Change-Id: Id812907cc6962ab7a9bb2ce8a7417ca0546363ab
CRs-Fixed: 2748373