sctp: remove useless start_fail from sctp_ht_iter in proc

After changing rhashtable_walk_start to return void, start_fail would
never be set other value than 0, and the checking for start_fail is
pointless, so remove it.

Fixes: 97a6ec4a

 ("rhashtable: Change rhashtable_walk_start to return void")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>