wifi: mwifiex: Remove unused mwifiex_uap_del_sta_data

The last use of mwifiex_uap_del_sta_data() was removed in 2014 by
commit dda9ddeb ("mwifiex: do not delete station entries in del_sta
handler")

Remove it.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://patch.msgid.link/20250204012512.390209-1-linux@treblig.org


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