Merge tag 'dma-mapping-4.14-2' of git://git.infradead.org/users/hch/dma-mapping

Pull dma mapping fix from Christoph Hellwig:
 "A fix for a fix that went in this merge window from Arnd"

* tag 'dma-mapping-4.14-2' of git://git.infradead.org/users/hch/dma-mapping:
  dma-coherent: fix rmem_dma_device_init regression