consolidate direct dma mapping and swiotlb support

[Christoph Hellwig]

On Fri, Dec 29, 2017 at 10:52:14AM +0000, Vladimir Murzin wrote:
> Is it available in your dma-mapping.git or somewhere else?

  git://git.infradead.org/users/hch/misc.git dma-direct

Gitweb:

  http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/dma-direct