to #28170604

commit 211fea18a7bb9b8d51cb5d2b9cbe5583af256609 upstream

An earlier commit "io_uring: remove @nxt from handlers" removed the
setting of pointer nxt and now it is always null, hence the non-null
check and call to io_wq_assign_next is redundant and can be removed.

Addresses-Coverity: ("'Constant' variable guard")
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Acked-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>