I was struggling to enable the SPI one my board too.
However i've found this tutorial that explain how to properly enable the SPI on the Pine64, which seem to work as well on the OrangePi Win+
http://synfare.com/599N105E/hwdocs/pine64/spidev.html
Because i have no access to SPI devices excepted my LoRa Gateway, i was not able to properly test the SPI Bus. Could you test if for me ?