iommu/exynos: Refactor function parameters to simplify code

This patch simplifies the code by:
- refactoring function parameters from struct device pointer to direct
  pointer to struct sysmmu drvdata
- moving list_head enteries from struct exynos_iommu_owner directly to
  struct sysmmu_drvdata

After above refactoring some functions were never used, so remove also
them completely.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Joerg Roedel <jroedel@suse.de>