libwifi: nlwifi_get_phy_wifi_ifaces with netdef

@anjancx @janusz @Marek please review

Allow nlwifi_get_phy_wifi_ifaces(const char *name ...) to be called with netdev as argument. It will be mapped to phy.

Signed-off-by: Bartlomiej Grzeskowiak bartlomiej.grzeskowiak@iopsys.eu