io_uring/napi: Remove unnecessary s64 cast

Since the do_div() macro casts the divisor to u32 anyway, remove the
unnecessary s64 cast and fix the following Coccinelle/coccicheck
warning reported by do_div.cocci:

  WARNING: do_div() does a 64-by-32 division, please consider using div64_s64 instead
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Link: https://lore.kernel.org/r/20240710010520.384009-2-thorsten.blum@toblux.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/napi.c

@@ -283,7 +283,7 @@ void __io_napi_adjust_timeout(struct io_ring_ctx *ctx, struct io_wait_queue *iow
 			s64 poll_to_ns = timespec64_to_ns(ts);
 			if (poll_to_ns > 0) {
 				u64 val = poll_to_ns + 999;
-				do_div(val, (s64) 1000);
+				do_div(val, 1000);
 				poll_to = val;
 			}
 		}