io_uring/net: initialize mshot_len for send

io_uring/net: initialize mshot_len for send

Commit:

6a8afb9fff64 ("io_uring/net: allow multishot receive per-invocation cap")

changed how io_mshot_prep_retry() set sr->len, and added the same
initialization in io_mshot_prep_retry(). But it neglected to touch the
send path, which may also uses the mshot retry path. Ensure that
sr->mshot_len always gets initialized correctly.

Fixes: 6a8afb9fff64 ("io_uring/net: allow multishot receive per-invocation cap")
Cc: stable@vger.kernel.org
Reported-by: Sung Keum <kambodi127@gmail.com>
Reviewed-by: Gabriel Krisman Bertazi <krisman@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>