iris: Export and import surfaces with modifiers that have aux data

iris: Export and import surfaces with modifiers that have aux data

The DRI interface for modifiers with aux data treats the aux data as a
separate plane of the main surface.

When the dri layer requests the plane associated with the aux data, we
save the required information into the dri aux plane image.

Later when the image is used, the dri plane image will be available in
the pipe_resource structure's `next` field. Therefore in iris, we
reconstruct the aux setup from this separate dri plane image when the
image is used.

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>