flexroad: ath5k band channels

* new 80211nl frequency band: IEEE80211_BAND_DSRC
* enable 802.11p channels (172-182) for ath5k
* add world domain regulatory rule to allow 172+ channels for
  ath5k/ath9k

Signed-off-by: Ildar Abubakirov <ildar.abubakirov@componentality.com>
flexroad-mac80211: 5.9GHz band regulatory rules

* new 5.9GHz band regulatory rules for RU, NL

Signed-off-by: Ildar Abubakirov <ildar.abubakirov@componentality.com>
flexroad: banner update

* sytem login banner updated

Signed-off-by: Ildar Abubakirov <ildar.abubakirov@componentality.com>
flexroad: rb411u network config

* several specific network options for flexroad devices

Signed-off-by: Ildar Abubakirov <ildar.abubakirov@componentality.com>