cfg80211: add request id parameter to .sched_scan_stop() signature

For multiple scheduled scan support the driver needs to know which
scheduled scan request is being stopped. Pass the request id in the
.sched_scan_stop() callback.

Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>