drm/radeon: fix VM IB handling

Calling radeon_vm_bo_find on the IB BO during CS
is illegal and can lead to an crash.

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/radeon_cs.c b/drivers/gpu/drm/radeon/radeon_cs.c
index 09fcf4d..ae763f6 100644
--- a/drivers/gpu/drm/radeon/radeon_cs.c
+++ b/drivers/gpu/drm/radeon/radeon_cs.c
@@ -472,13 +472,13 @@
 	if (r)
 		return r;
 
-	bo_va = radeon_vm_bo_find(vm, rdev->ring_tmp_bo.bo);
-	if (bo_va == NULL) {
+	if (vm->ib_bo_va == NULL) {
 		DRM_ERROR("Tmp BO not in VM!\n");
 		return -EINVAL;
 	}
 
-	r = radeon_vm_bo_update(rdev, bo_va, &rdev->ring_tmp_bo.bo->tbo.mem);
+	r = radeon_vm_bo_update(rdev, vm->ib_bo_va,
+				&rdev->ring_tmp_bo.bo->tbo.mem);
 	if (r)
 		return r;