staging: rtl8188eu: use safe iterator in expire_timeout_chk

staging: rtl8188eu: use safe iterator in expire_timeout_chk

In the first loop in expire_timeout_chk, we may call rtw_free_stainfo and
remove an entry from auth_list.

In the second loop, we may call list_del_init on our list.

Use list_for_each_entry_safe for both loops.

Fixes: 23017c8842d2 ("staging: rtl8188eu: Use list iterators and helpers")
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210517201826.25150-3-martin@kaiser.cx
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>