drm/exynos: added cache attribute support for gem.

with this patch, user application can set cache attribute(such as
cachable, writecombime or non-cachable) of the memory region allocated
by gem framework.

Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
diff --git a/include/drm/exynos_drm.h b/include/drm/exynos_drm.h
index e478de4..2d6eb06 100644
--- a/include/drm/exynos_drm.h
+++ b/include/drm/exynos_drm.h
@@ -95,9 +95,18 @@
 
 /* memory type definitions. */
 enum e_drm_exynos_gem_mem_type {
+	/* Physically Continuous memory and used as default. */
+	EXYNOS_BO_CONTIG	= 0 << 0,
 	/* Physically Non-Continuous memory. */
 	EXYNOS_BO_NONCONTIG	= 1 << 0,
-	EXYNOS_BO_MASK		= EXYNOS_BO_NONCONTIG
+	/* non-cachable mapping and used as default. */
+	EXYNOS_BO_NONCACHABLE	= 0 << 1,
+	/* cachable mapping. */
+	EXYNOS_BO_CACHABLE	= 1 << 1,
+	/* write-combine mapping. */
+	EXYNOS_BO_WC		= 1 << 2,
+	EXYNOS_BO_MASK		= EXYNOS_BO_NONCONTIG | EXYNOS_BO_CACHABLE |
+					EXYNOS_BO_WC
 };
 
 #define DRM_EXYNOS_GEM_CREATE		0x00