mac80211: add handling for BSS color

It is now possible to propagate BSS color settings into the subsystem. Lets
make mac80211 also handle them so that we can send them further down the
stack into the drivers. We drop the old bss_color field and change iwlwifi
to use the new he_bss_color struct.

Signed-off-by: John Crispin <john@phrozen.org>
Link: https://lore.kernel.org/r/20191217141921.8114-2-john@phrozen.org


Signed-off-by: Johannes Berg <johannes.berg@intel.com>