wifi: nl80211: disallow setting special AP channel widths

Setting the AP channel width is meant for use with the normal
20/40/... MHz channel width progression, and switching around
in S1G or narrow channels isn't supported. Disallow that.

Reported-by:  <syzbot+bc0f5b92cc7091f45fb6@syzkaller.appspotmail.com>
Link: https://msgid.link/20240515141600.d4a9590bfe32.I19a32d60097e81b527eafe6b0924f6c5fbb2dc45@changeid


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