Merge ranch 'topic-0620/samsung-vb2-3.4' into chromeos-exynos-3.4

Merge ranch 'topic-0620/samsung-vb2-3.4' into chromeos-exynos-3.4

* topic-0620/samsung-vb2-3.4: (28 commits)
  FIX: add blank mmap function support for dma_buf_ops
  MEDIA: Support of dma_buf export in v4l2-m2m
  v4l: vb2-dma-contig: use dma_get_sgtable
  v4l: s5p-mfc: support for dmabuf exporting
  v4l: s5p-tv: mixer: support for dmabuf exporting
  v4l: s5p-fimc: support for dmabuf exporting
  v4l: vb2-dma-contig: add support for DMABUF exporting
  v4l: vb2: add buffer exporting via dmabuf
  v4l: add buffer exporting via dmabuf
  Documentation: media: description of DMABUF exporting in V4L2
  v4l: vb2-dma-contig: let mmap method to use dma_mmap_coherent call
  UPSTREAM: [media] v4l2-ioctl: handle priority handling based on a table lookup
  UPSTREAM: [media] v4l2-dev/ioctl: determine the valid ioctls upfront
  UPSTREAM: [media] v4l2-dev: make it possible to skip locking for selected ioctls
  v4l: s5p-tv: mixer: support for dmabuf importing
  v4l: vivi: support for dmabuf importing
  v4l: vb2-vmalloc: add support for dmabuf importing
  v4l: vb2-dma-contig: add support for dma_buf importing
  v4l: vb2-dma-contig: add prepare/finish to dma-contig allocator
  v4l: vb2: add prepare/finish callbacks to allocators
  ...