qcacld-3.0: Stop bus bandwidth work with timer

The bus bandwidth compute timer is a periodic timer which computes bus
bandwidth usage of associated adapters over a period of time. When the
last adapter disassociates, this timer is stopped. However, the timer
starts a work that is not stopped or flushed at this time. When the
device is under load from external subsystems, this work can get pushed
out past what is safe. When the bus bandwidth timer is stopped, also
stop and flush the bus bandwidth work to ensure safe memory access.

Change-Id: I32c15b42c9756341d1ecf534c05f87738fd24edb
CRs-Fixed: 2300697
2 files changed