zynq: add debug messages to HITL test

zynq.nix

@@ -35,16 +35,20 @@ in
 
       buildPhase =
         ''
+        echo Power cycling board...
         (echo b; sleep 5; echo B) | nc -N 192.168.1.31 3131
         sleep 5
+        echo Power cycle done.
 
         export USER=hydra
         pushd ${<artiq-zynq>}
         bash ${<artiq-zynq>}/remote_run.sh -h rpi-4 -o "-F /dev/null -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o LogLevel=ERROR -i /opt/hydra_id_rsa" -d ${artiq-zynq.zc706-simple-jtag}
         popd
 
+        echo Waiting for the firmware to boot...
         sleep 15
 
+        echo Running test kernel...
         artiq_run --device-db ${<artiq-zynq>}/examples/device_db.py ${<artiq-zynq>}/examples/mandelbrot.py
 
         touch $out