io_uring/net: dedup io_recv_finish req completion

There are two block in io_recv_finish() completing the request, which we
can combine and remove jumping.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0e338dcb33c88de83809fda021cba9e7c9681620.1709905727.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>