drm/exynos: fix iommu address allocation order

This patch modifies iommu address allocation order from 64k
to 4k. 64k order causes waste of the io space and this was
our mistakes.
Signed-off-by: NInki Dae <inki.dae@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_iommu.h

@@ -14,7 +14,7 @@
 
 #define EXYNOS_DEV_ADDR_START	0x20000000
 #define EXYNOS_DEV_ADDR_SIZE	0x40000000
-#define EXYNOS_DEV_ADDR_ORDER	0x4
+#define EXYNOS_DEV_ADDR_ORDER	0x0
 
 #ifdef CONFIG_DRM_EXYNOS_IOMMU