iommu/exynos: Remove useless members from exynos_iommu_owner structure

This patch removes useless spinlocks and other unused members from
struct exynos_iommu_owner. There is no point is protecting this
structure by spinlock because content of this structure doesn't change
and other structures have their own spinlocks.

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>