wifi: mac80211: move some future per-link data to bss_conf

To add MLD, reuse the bss_conf structure later for per-link
information, so move some things into it that are per link.

Most transformations were done with the following spatch:

    @@
    expression sdata;
    identifier var = { chanctx_conf, mu_mimo_owner, csa_active, color_change_active, color_change_color };
    @@
    -sdata->vif.var
    +sdata->vif.bss_conf.var

    @@
    struct ieee80211_vif *vif;
    identifier var = { chanctx_conf, mu_mimo_owner, csa_active, color_change_active, color_change_color };
    @@
    -vif->var
    +vif->bss_conf.var

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