[util] Display Python lint error messages

The lintpy utility currently doesn't display the output from the linter
unless the `--fix` option is used, which isn't available for flake8 at
all. Change the script to output the linter stdout/stderr in all cases.

Signed-off-by: Philipp Wagner <phw@lowrisc.org>
diff --git a/util/lintpy.py b/util/lintpy.py
index aa4d502..dc4c9c0 100755
--- a/util/lintpy.py
+++ b/util/lintpy.py
@@ -61,8 +61,6 @@
         return (True, True)
     except subprocess.CalledProcessError as exc:
         sys.stderr.write('Lint failed:\n  {}\n'.format(' '.join(check_cmd)))
-        if not dofix or fix is None:
-            return (True, True)
 
         if exc.output:
             output = exc.output.decode(sys.getfilesystemencoding())
@@ -71,6 +69,9 @@
                   sep='',
                   file=sys.stderr)
 
+        if not dofix or fix is None:
+            return (True, True)
+
     print("Fixing...", file=sys.stderr)
     subprocess.check_call(fix + files,
                           stderr=subprocess.STDOUT,