[bazel] add rules for misc python scripts

There are misc. python scripts used to scramble ROM images, produce ECC
bits for flash images, and generate a version string for ROM. Bazel
rules have been added to properly refer to these scripts with Python
Bazel rules.

Signed-off-by: Timothy Trippel <ttrippel@google.com>
diff --git a/util/rom_chip_info.py b/util/rom_chip_info.py
index 66b1cc0..546cb7d 100755
--- a/util/rom_chip_info.py
+++ b/util/rom_chip_info.py
@@ -7,13 +7,10 @@
 
 import argparse
 import logging as log
-import os
 import sys
 from datetime import datetime
-from io import StringIO
 from pathlib import Path
 
-
 header_template = r"""
 // Copyright lowRISC contributors.
 // Licensed under the Apache License, Version 2.0, see LICENSE for details.
@@ -31,21 +28,20 @@
 #endif  // _F_CHIPINFO_H__
 
 """
+
+
 def main():
     parser = argparse.ArgumentParser(prog="rom_chip_info")
     parser.add_argument('--outdir',
                         '-o',
                         required=True,
-                        help='Output Directory'
-                        )
+                        help='Output Directory')
     parser.add_argument('--ot_version',
                         required=False,
-                        help='OpenTitan Version'
-                        )
+                        help='OpenTitan Version')
     parser.add_argument('--ot_version_file',
                         required=False,
-                        help='Path to a file with the OpenTitan Version'
-                        )
+                        help='Path to a file with the OpenTitan Version')
 
     log.basicConfig(format="%(levelname)s: %(message)s")
     args = parser.parse_args()
@@ -60,8 +56,7 @@
         version = open(args.ot_version_file, "rt").read().strip()
     else:
         log.error(
-            "Missing ot_version, provide --ot_version or --ot_version_file."
-        )
+            "Missing ot_version, provide --ot_version or --ot_version_file.")
         raise SystemExit(sys.exc_info()[1])
 
     outdir = Path(args.outdir)
@@ -72,8 +67,8 @@
     now = datetime.now()
     wall_time = now.strftime("%Y-%m-%d, %H:%M:%S")
 
-    log.info("Version: %s" % (version,))
-    log.info("Build Date: %s" % (wall_time,))
+    log.info("Version: %s" % (version, ))
+    log.info("Build Date: %s" % (wall_time, ))
 
     output = header_template
     output = output.replace('{%version%}', version, 1)