drm/radeon/radeon_ttm: Remove unused variable 'rbo' from radeon_bo_move()

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/radeon/radeon_ttm.c: In function ‘radeon_bo_move’:
 drivers/gpu/drm/radeon/radeon_ttm.c:201:27: warning: variable ‘rbo’ set but not used [-Wunused-but-set-variable]
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_ttm.c

@@ -197,7 +197,6 @@ static int radeon_bo_move(struct ttm_buffer_object *bo, bool evict,
 {
 	struct ttm_resource *old_mem = bo->resource;
 	struct radeon_device *rdev;
-	struct radeon_bo *rbo;
 	int r;
 
 	if (new_mem->mem_type == TTM_PL_TT) {
@@ -210,7 +209,6 @@ static int radeon_bo_move(struct ttm_buffer_object *bo, bool evict,
 	if (r)
 		return r;
 
-	rbo = container_of(bo, struct radeon_bo, tbo);
 	rdev = radeon_get_rdev(bo->bdev);
 	if (!old_mem || (old_mem->mem_type == TTM_PL_SYSTEM &&
 			 bo->ttm == NULL)) {