K8T900, like all other AMD64 chipsets, is completely agnostic to what CPU socket or type you use. There is no such thing as "chipset specifically designed for socket XXX" in this architecture.
For M2, chipsets may bring support for higher HT link speeds - but that doesn't mean they aren't just as good on any one of the three existing socket types.
In other words, there is no technical excuse for the lack of boards using this chipset - other than actual chip availability in mass quantities.