drm: store the gem vma offset manager in a typed pointer

This was hidden in a generic void * dev->mm_private. But only ever
used for gem. But thanks to this fake generic pretension no one
noticed that Rob's drm drivers are now all broken.

So just give the offset manager a type pointer and fix up msm, omapdrm
and tilcdc.

v2: Fixup compile fail.

v3: Fixup rebase fail that David spotted.

Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/omapdrm/omap_debugfs.c b/drivers/gpu/drm/omapdrm/omap_debugfs.c
index c27f59d..d4c04d6 100644
--- a/drivers/gpu/drm/omapdrm/omap_debugfs.c
+++ b/drivers/gpu/drm/omapdrm/omap_debugfs.c
@@ -48,7 +48,7 @@
 {
 	struct drm_info_node *node = (struct drm_info_node *) m->private;
 	struct drm_device *dev = node->minor->dev;
-	return drm_mm_dump_table(m, dev->mm_private);
+	return drm_mm_dump_table(m, &dev->vma_offset_manager->vm_addr_space_mm);
 }
 
 static int fb_show(struct seq_file *m, void *arg)