The current error state harks back to the era of just a single VM. For
full-ppgtt, we capture every bo on every VM. It behoves us to then print
every bo for every VM, which we currently fail to do and so miss vital
information in the error state.

v2: Use the vma address rather than -1!
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>