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.h b/drivers/gpu/drm/radeon/radeon.h
index 3d5e1a9..60c47f8 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -879,6 +879,8 @@
 	/* array of page tables, one for each page directory entry */
 	struct radeon_vm_pt		*page_tables;
 
+	struct radeon_bo_va		*ib_bo_va;
+
 	struct mutex			mutex;
 	/* last fence for cs using this vm */
 	struct radeon_fence		*fence;