staging: rtl8723bs: remove dead code, rtw_port_switch_chk()

The function rtw_port_switch_chk() returns always false.
Remove the function and related dead code.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>