cfg80211: add scan time to survey data

Add the time spent scanning to the survey data so it can be
reported by drivers that collect such information.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --cc include/net/cfg80211.h
Simple merge

diff --cc include/uapi/linux/nl80211.h
Simple merge

diff --cc net/wireless/nl80211.c
Simple merge

diff --cc net/wireless/trace.h
Simple merge