iommu/exynos: Add support for binding more than one sysmmu to master device

This patch adds support for assigning more than one SYSMMU controller to
the master device. This has been achieved simply by chaning the struct
device pointer in struct exynos_iommu_owner into the list of struct
sysmmu_drvdata of all controllers assigned to the given master device.

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>