I had the same problem with an Intel Centrino 2230 (Galileo Gen 2) and a Realtek RTL8188CUS USB Wireless Adaptor (Galileo Gen 1)
Removing connman fixed it.
But before you do, maybe you should use AlexT's version of Yocto that includes connection to his repository or manually set up a connection so you can put it back if needed.
see Updated Galileo "devtools" image is out
then run
opkg remove connman
it will hang a long time on stopping connman, but when you reboot it should be gone
You can check with opkg list |grep connman
rgb