staging: rtl8723bs: Remove Dead Code in core/rtw_mlme.c

The Functions `void rtw_surveydone_event_callback`, `void rtw_indicate_connect`,
`void rtw_stadel_event_callback` and `void _rtw_join_timeout_handler`
are using the Macro CONFIG_INTEL_WIDI which doesn't exists anymore.

Signed-off-by: Emanuel Bennici <benniciemanuel78@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>