Take core part of find_device_iter() to make a new function
is_error_source() that checks given device has report an error
or not.
Signed-off-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Reviewed-by: NKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>