drm/radeon/kms/r6xx+: add query for tile config (v2)

Userspace needs this information to access tiled
buffers via the CPU.

v2: rebased on evergreen accel changes

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/rv770.c b/drivers/gpu/drm/radeon/rv770.c
index 836c15a..236fe66 100644
--- a/drivers/gpu/drm/radeon/rv770.c
+++ b/drivers/gpu/drm/radeon/rv770.c
@@ -674,8 +674,9 @@
 								 r600_count_pipe_bits((cc_rb_backend_disable &
 										       R7XX_MAX_BACKENDS_MASK) >> 16)),
 								(cc_rb_backend_disable >> 16));
-	gb_tiling_config |= BACKEND_MAP(backend_map);
 
+	rdev->config.rv770.tile_config = gb_tiling_config;
+	gb_tiling_config |= BACKEND_MAP(backend_map);
 
 	WREG32(GB_TILING_CONFIG, gb_tiling_config);
 	WREG32(DCP_TILING_CONFIG, (gb_tiling_config & 0xffff));