The walk from input is the list header, and marked as dead, and will
be skipped in loop.

list_first_entry() can be used to return the true usable value from
walk if walk is not empty
Signed-off-by: NLi RongQing <roy.qing.li@gmail.com>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NSteffen Klassert <steffen.klassert@secunet.com>