drm/exynos: remove EXYNOS_BO_NONCONTIG type checking.

With iommu support, non-continuous buffer also is supported so
this patch removes these checking from exynos_drm_gem_get/put_dma_addr
funciton.

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>