enable error LED on pll lock fail

src/runtime/src/rtio_clocking.rs

@@ -96,6 +96,11 @@ fn init_rtio(timer: &mut GlobalTimer, _clk: RtioClock) {
         info!("RTIO PLL locked");
     } else {
         error!("RTIO PLL failed to lock");
+        #[cfg(feature = "target_kasli_soc")]
+        {
+            pl::csr::error_led::out_write(1);
+            // try "soft" panic
+        }
     }
 
     unsafe {