decoder: clippy (div_ceil, if let), which CI's -D warnings refused

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz

src/decoder/layout.rs

@@ -29,7 +29,7 @@ pub struct Layout {
 impl Layout {
     /// Bytes the frame must carry for this signal to be read.
     pub fn needs(&self) -> usize {
-        self.byte + (self.length as usize + 7) / 8
+        self.byte + (self.length as usize).div_ceil(8)
     }
 
     /// The signal's value from a frame's data, or None when the frame is too short.

src/decoder/main.rs

@@ -284,13 +284,11 @@ fn main() -> ExitCode {
     loop {
         if sock.is_none() && last_open_try.elapsed() >= Duration::from_secs(2) {
             last_open_try = Instant::now();
-            match socket::RxSocket::open(&iface, &ids, Duration::from_millis(100)) {
-                Ok(s) => {
+            // Absent or down: the state says so, retried every 2 s.
+            if let Ok(s) = socket::RxSocket::open(&iface, &ids, Duration::from_millis(100)) {
                 eprintln!("decoder: {iface} open");
                 sock = Some(s);
             }
-                Err(_) => {} // absent or down: the state says so, retried every 2 s
-            }
         }
         match sock.as_ref().map(|s| s.recv()) {
             Some(Ok(Some(f))) => {