cfg80211: clean up cfg80211_inform_single_bss_frame_data()

cfg80211_inform_single_bss_frame_data() doesn't need the
non_tx_data data argument since it's always NULL.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>
Link: https://lore.kernel.org/r/20190703133823.10530-1-johannes@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>