Revert "nl80211/cfg80211: Specify band specific min RSSI thresholds with sched scan"

This *mostly* reverts commit 1e1b11b6

 ("nl80211/cfg80211: Specify
band specific min RSSI thresholds with sched scan").

During the review of a new patch [1] it was observed that the
functionality being modified was not actually being used by any
in-tree driver. Further research determined that the functionality was
originally introduced to support a new Android interface, but that
interface was subsequently abandoned. Since the functionality has
apparently never been used, remove it. However, to mantain the
sanctity of the UABI, keep the nl80211.h assignments, but clearly mark
them as obsolete.

Cc: Lin Ma <linma@zju.edu.cn>
Cc: Vamsi Krishna <quic_vamsin@quicinc.com>
Link: https://lore.kernel.org/linux-wireless/20240119151201.8670-1-linma@zju.edu.cn/ [1]
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Link: https://msgid.link/20240125-for-next-v1-1-fd79e01c6c09@quicinc.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>