io_uring/poll: improve readability of poll reference decrementing

This overly long line is hard to read. Break it up by AND'ing the
ref mask first, then perform the atomic_sub_return() with the value
itself.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/poll.c

@@ -343,8 +343,8 @@ static int io_poll_check_events(struct io_kiocb *req, struct io_tw_state *ts)
 		 * Release all references, retry if someone tried to restart
 		 * task_work while we were executing it.
 		 */
-	} while (atomic_sub_return(v & IO_POLL_REF_MASK, &req->poll_refs) &
-					IO_POLL_REF_MASK);
+		v &= IO_POLL_REF_MASK;
+	} while (atomic_sub_return(v, &req->poll_refs) & IO_POLL_REF_MASK);
 
 	return IOU_POLL_NO_ACTION;
 }