convert drivers/block to the generic DMA API

To: Jens Axboe <axboe@xxxxxxxxx>
Subject: convert drivers/block to the generic DMA API
From: Christoph Hellwig <hch@xxxxxx>
Date: Thu, 18 Oct 2018 15:15:10 +0200
Cc: Joshua Morris <josh.h.morris@xxxxxxxxxx>, Philip Kelleher <pjk1939@xxxxxxxxxxxxxxxxxx>, linux-block@xxxxxxxxxxxxxxx

Switch all remaining users of the legacy PCI DMA API to the
generic DMA API.

Follow-Ups:
- Re: convert drivers/block to the generic DMA API
  - From: Jens Axboe
- [PATCH 6/6] mtip32xx: fully switch to the generic DMA API
  - From: Christoph Hellwig
- [PATCH 5/6] rsxx: switch to the generic DMA API
  - From: Christoph Hellwig
- [PATCH 4/6] umem: switch to the generic DMA API
  - From: Christoph Hellwig
- [PATCH 3/6] sx8: switch to the generic DMA API
  - From: Christoph Hellwig
- [PATCH 2/6] sx8: remove dead IF_64BIT_DMA_IS_POSSIBLE code
  - From: Christoph Hellwig
- [PATCH 1/6] skd: switch to the generic DMA API
  - From: Christoph Hellwig