When sta+sap scc enabled on dfs channel then SAP cannot operate on
DFS channel in standalone mode. If STA+SAP are operating in SCC mode
on a DFS channel and STA gets disconnected from reference AP then driver
schedules a workqueue to move the SAP from DFS channel to user configured
channel. At this time if STA again connects to reference AP within few ms
then driver again schedules one more workqueue to move the SAP to STA's
channel. Sometimes the second workqueue may fail to switch the channel
if first one is not yet completed. So added event variable to schedule
second workqueue only when first one is complete.
CRs-Fixed: 2267005
Change-Id: Ia6ce4b6264c35f6d2c809e2a3f65f535e930874e