tools: fix invalid escape sequence in mkssldef

Use a raw string for the regex.

PR-URL: #52624
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Mohammed Keyvanzadeh <mohammadkeyvanzade94@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

tools/mkssldef.py

@@ -26,7 +26,7 @@
 
   for filename in filenames:
     for line in open(filename).readlines():
-      name, _, _, meta, _ = re.split('\s+', line)
+      name, _, _, meta, _ = re.split(r'\s+', line)
       if any(p.match(name) for p in excludes): continue
       meta = meta.split(':')
       assert meta[0] in ('EXIST', 'NOEXIST')