I followed the instructions at this location: http://www.wiki.xilinx.com/Build+Device+Tree+Blob to try to create a modified device tree.
I was able to select device-tree under the OS menu in the Board Support Package menu. However, SDK crashed when I tried to modify the board support package. This occurred in Windows 7 and in Linux OS.
This issue is related to the naming format of the device tree.
To resolve this issue, follow the naming format below for the device tree:
Once the device tree has been renamed, update the SDK repository (Xilinx Tools -> Repositories, Rescan Repositories).
Rebuild the BSP and try again.