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>

configs/common/SimpleOpts.py

@@ -44,6 +44,7 @@ from argparse import ArgumentParser
 # add the args we want to be able to control from the command line
 parser = ArgumentParser()
 
+
 def add_option(*args, **kwargs):
     """Call "add_option" to the global options parser
     """
@@ -53,12 +54,13 @@ def add_option(*args, **kwargs):
 
     parser.add_argument(*args, **kwargs)
 
+
 def parse_args():
     global called_parse_args
     called_parse_args = True
 
     return parser.parse_args()
 
+
 def print_help(*args, **kwargs):
     parser.print_help(*args, **kwargs)
-