clearly mark DMA_OPS support as an architecture feature v2

[Michael S. Tsirkin]

On Tue, Sep 03, 2024 at 09:27:44AM +0200, Christoph Hellwig wrote:
> I've pulled this into the dma-mapping for-next tree, although I'd
> love to see one of the vdpa maintainers look over patch 1.  I'm
> pretty sure it's correct, but a confirmation would be good.

Missed patch 1, I was wondering why I'm CC'd. Looks good, thanks.