python: Apply Black formatter to Python files

The command executed was `black src configs tests util`.

Change-Id: I8dfaa6ab04658fea37618127d6ac19270028d771
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/47024
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>

util/git-pre-commit.py

@@ -36,7 +36,6 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 
-
 from tempfile import TemporaryFile
 import os
 import subprocess
@@ -48,11 +47,11 @@ from style.style import StdioUI, check_ignores
 
 import argparse
 
-parser = argparse.ArgumentParser(
-    description="gem5 git style checker hook")
+parser = argparse.ArgumentParser(description="gem5 git style checker hook")
 
-parser.add_argument("--verbose", "-v", action="store_true",
-                    help="Produce verbose output")
+parser.add_argument(
+    "--verbose", "-v", action="store_true", help="Produce verbose output"
+)
 
 args = parser.parse_args()
 
@@ -80,16 +79,22 @@ for status, fname in git.status(filter="MA", cached=True):
     try:
         status = git.file_from_index(fname)
     except UnicodeDecodeError:
-        print("Decoding '" + fname
-            + "' throws a UnicodeDecodeError.", file=sys.stderr)
-        print("Please check '" + fname
-            + "' exclusively uses utf-8 character encoding.", file=sys.stderr)
+        print(
+            "Decoding '" + fname + "' throws a UnicodeDecodeError.",
+            file=sys.stderr,
+        )
+        print(
+            "Please check '"
+            + fname
+            + "' exclusively uses utf-8 character encoding.",
+            file=sys.stderr,
+        )
         sys.exit(1)
 
     f = TemporaryFile()
-    f.write(status.encode('utf-8'))
+    f.write(status.encode("utf-8"))
 
-    verifiers = [ v(ui, opts, base=repo_base) for v in all_verifiers ]
+    verifiers = [v(ui, opts, base=repo_base) for v in all_verifiers]
     for v in verifiers:
         f.seek(0)
         # It is prefered that the first check is silent as it is in the
@@ -113,14 +118,17 @@ if failing_files:
             "Please run the style checker manually to fix "
             "the offending files.\n"
             "To check your modifications, run: util/style.py -m",
-            file=sys.stderr)
+            file=sys.stderr,
+        )
 
     print("\n", file=sys.stderr)
     if staged_mismatch:
         print(
             "It looks like you have forgotten to stage your "
             "fixes for commit in\n"
-            "the following files: ", file=sys.stderr)
+            "the following files: ",
+            file=sys.stderr,
+        )
         for f in staged_mismatch:
             print("\t{}".format(f), file=sys.stderr)
         print("Please `git --add' them", file=sys.stderr)