By having a pointer to the root port link, we can remove loops in
get_root_port_link() to search the root port link.
Acked-by: NShaohua Li <shaohua.li@intel.com>
Signed-off-by: NKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>