scripts/checkpatch: Improve the check for authors mangled by the mailing list

scripts/checkpatch: Improve the check for authors mangled by the mailing list

There were recently some patches on the list which had their "From:"
line mangled like this:

 From: qemu_oss--- via <qemu-devel@nongnu.org>

Since our test in the checkpatch.pl script did not trigger here, the
patches finally also ended up in a pull request, with the wrong author
set. So let's improve the regular expression to also complain on
these new patterns, too.

Message-Id: <20210216071512.1199827-1-thuth@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>