Fix warnings introduced with rust 1.82

Author: usbalbin

examples/can-echo.rs

@@ -122,8 +122,7 @@ fn main() -> ! {
     block!(can.transmit(header, &buffer)).unwrap();
 
     loop {
-        if let Ok(rxheader) = block!(can.receive0(&mut buffer)) {
-            block!(can.transmit(rxheader.unwrap().to_tx_header(None), &buffer)).unwrap();
-        }
+        let Ok(rxheader) = block!(can.receive0(&mut buffer));
+        block!(can.transmit(rxheader.unwrap().to_tx_header(None), &buffer)).unwrap();
     }
 }