Merge tag 'dma-mapping-4.13-2' of git://git.infradead.org/users/hch/dma-mapping

Pull dma mapping fixes from Christoph Hellwig:
 "split the global dma coherent pool from the per-device pool.

  This fixes a regression in the earlier 4.13 pull requests where the
  global pool would override a per-device CMA pool (Vladimir Murzin)"

* tag 'dma-mapping-4.13-2' of git://git.infradead.org/users/hch/dma-mapping:
  ARM: NOMMU: Wire-up default DMA interface
  dma-coherent: introduce interface for default DMA pool