iommu/exynos: use convenient macro to handle gate clocks

exynos-iommu driver must care about master H/W's gate clock as well as
System MMU's gate clock. To enhance readability of the source code,
macros to gate/ungate those clocks are defined.

Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
1 file changed