cfg80211: Pass lockdep expression to RCU lists

cfg80211: Pass lockdep expression to RCU lists

rdev->sched_scan_req_list maybe traversed using list_for_each_entry_rcu
outside an RCU read-side critical section but under the protection
of rtnl_mutex.

Hence, add corresponding lockdep expression to silence false-positive
warnings, and harden RCU lists.

Signed-off-by: Amol Grover <frextrite@gmail.com>
Link: https://lore.kernel.org/r/20200219091102.10709-1-frextrite@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>