misc: Run pre-commit run on all files in repo

The following command was run:

```
pre-commit run --all-files
```

This ensures all the files in the repository are formatted to pass our
checks.

Change-Id: Ia2fe3529a50ad925d1076a612d60a4280adc40de
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/62572
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>

util/tracediff

@@ -146,6 +146,3 @@ $fullcmd = "$FindBin::Bin/rundiff '$cmd1' '$cmd2' 2>&1 > tracediff-$$.out";
 
 print "Executing $fullcmd\n";
 system($fullcmd);
-
-
-