don´t need be specifically spidev1.1 but as i can saw on document " Intel® Quark SoC X1000 Board Support Package (BSP)" we just have available:
so, spidev3.8 it is weird for me.
According to the repositories for the iot-devkit image, you should be able to use this.
Try to use an Ethernet or WiFi connection and run in your Terminal Console:
opkg install http://iotdk.intel.com/repos/1.1/iotdk/quark/kernel-module-spidev_3.8-r0_quark.ipk
Let me know the outcome of this.