drm/tegra: Add IOMMU support

When an IOMMU device is available on the platform bus, allocate an IOMMU
domain and attach the display controllers to it. The display controllers
can then scan out non-contiguous buffers by mapping them through the
IOMMU.

Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --cc drivers/gpu/drm/tegra/dc.c
Simple merge

diff --cc drivers/gpu/drm/tegra/drm.c
Simple merge

diff --cc drivers/gpu/drm/tegra/drm.h
Simple merge

diff --cc drivers/gpu/drm/tegra/fb.c
Simple merge

diff --cc drivers/gpu/drm/tegra/gem.c
Simple merge

diff --cc drivers/gpu/drm/tegra/gem.h
Simple merge