PI: display: slower refresh rate

Signed-off-by: Frank Villaro-Dixon <frank@villaro-dixon.eu>

pi/display/src/main.rs

@@ -149,7 +149,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         }
 
         rate.update(get_chrony_ntp_hits());
-        std::thread::sleep(Duration::from_millis(100));
+        std::thread::sleep(Duration::from_millis(300));
     }
 
     Ok(())