The Zynq-7000 Software Developers Guide (UG821) mentions that SDK supports Linux BSP and device tree generation for peripherals in the PS as well as custom IP in the PL.
However, I do not see the option for generation of the device tree in the SDK GUI.
The Xilinx wiki contains information about adding and using the Xilinx device tree generator with SDK. Please see this page for more details:
Note that currently (ISE Design Suite 14.3), the Device Tree Generator support is functional but incomplete. Full support is expected in a future release.