The APs will snoop DHCP by default to determine a client's IP address (as well as operating system). Is that what you meant by DHCP snooping, or is there something else you were looking for?
There is also an "IP Spoof" detection feature in the IP DOS filters section which will prevent clients from spoofing multiple IP addresses. You access from the SSID configuration, in the "DoS Prevention and Filters" portion of the Optional settings near the bottom. Look for the "IP DoS Per SSID" section and click the + to create a new DoS filter. Name it, check the box for "Ip Spoof" and pick an appropriate reaction (alarm, ban, etc...). It's not exactly the same as IP Source Guard, but it might be close enough depending on what you are trying to do.