drm/radeon/kms: fix and unify tiled buffer alignment checking for r6xx/7xx

Tiled buffers have the same alignment requirements regardless of
whether the surface is for db, cb, or textures.  Previously, the
calculations where inconsistent for each buffer type.

- Unify the alignment calculations in a common function
- Standardize the alignment units (pixels for pitch/height/depth,
bytes for base)
- properly check the buffer base alignments

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/r600d.h

@@ -51,6 +51,12 @@
 #define PTE_READABLE				(1 << 5)
 #define PTE_WRITEABLE				(1 << 6)
 
+/* tiling bits */
+#define     ARRAY_LINEAR_GENERAL              0x00000000
+#define     ARRAY_LINEAR_ALIGNED              0x00000001
+#define     ARRAY_1D_TILED_THIN1              0x00000002
+#define     ARRAY_2D_TILED_THIN1              0x00000004
+
 /* Registers */
 #define	ARB_POP						0x2418
 #define 	ENABLE_TC128					(1 << 30)