of current
process to manage gem handles to owner.

This patch is based on the below patch set, "drm/exynos: add
iommu support for -next".
     http://www.spinics.net/lists/dri-devel/msg29041.html

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
~ân