helpers: frontend: deviceinfo_parse: print meta-info to stderr

For the JSON output to be machine-readable we can't have random other
logging messages in the mix. Print the metadata to stderr instead of
stdout.

Signed-off-by: Caleb Connolly <caleb@postmarketos.org>

pmb/helpers/frontend.py

@@ -465,7 +465,7 @@ def deviceinfo_parse(args: PmbArgs) -> None:
     # Iterate over all devices
     kernel = args.deviceinfo_parse_kernel
     for device in devices:
-        print(f"{device}, with kernel={kernel}:")
+        print(f"{device}, with kernel={kernel}:", file=sys.stderr)
         print(json.dumps(pmb.parse.deviceinfo(device, kernel), indent=4, sort_keys=True))