Allow unsafe with log-itm feature flag for examples

Whilst still allowing #![deny(unsafe_code)] in the examples themselves

Author: richardeoin

examples/utilities/logger.rs

@@ -1,3 +1,5 @@
+#![cfg_attr(feature = "log-itm", allow(unsafe_code))]
+
 cfg_if::cfg_if! {
     if #[cfg(any(feature = "log-itm"))] {
         use panic_itm as _;