staging: rtl8723bs: Remove Dead Functions in os_dep/ioctl_linux.c

The Functions `static int rtw_widi_set()` and
`static int rtw_widi_set_probe_request()` part of dead code due to
CONFIG_INTEL_WIDI.
The fix removes the deadcode.

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