remove prints in uart Iterator impl

src/modem.rs

@@ -58,12 +58,9 @@ impl<UART: serial::Uart> Iterator for IterableRx<UART> {
                     break Some(b)
                 },
                 _ => {
-                    print!("got into retry loop in read iterator, ");
                     if now.elapsed() > timeout {
-                        println!("exiting because timeout expired :(");
                         break None
                     }
-                    println!("waiting 200ms ...");
                     thread::sleep(Duration::from_millis(200));
                     self.timeout = Some(timeout - now.elapsed());
                 }