cfg80211: fix few minor issues in reg_process_hint()
Fix the following issues in reg_process_hint():
1. Add verification that wiphy is valid before processing
NL80211_REGDOMAIN_SET_BY_COUNTRY_IE.
2. Free the request in case of invalid initiator.
3. Remove WARN_ON check on reg_request->alpha2 as it is not a
pointer.
Signed-off-by: Ilan Peer <ilan.peer@intel.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com>