I think there is an error in the device tree provided with SDK 01.00.00.03.
In am33xx.dtsi, the resource property interrupts-names is used, but the kernel documentation says that it should be interrupt-names (no s on interrupts).
It seems that the kernel source in this SDK doesn't use that anyway, but it will matter in the future. I had to add a couple of functions to get the current code to enable the interrupt, after fixing the device tree.
Andrew