selftests: drv-net: Fix TSO test doc

Replace copy paste from csum.py with a real test purpose.

Signed-off-by: Petr Vorel <pvorel@suse.cz>
Link: https://patch.msgid.link/20260720215149.631145-2-pvorel@suse.cz
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/drivers/net/hw/tso.py

@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 
-"""Run the tools/testing/selftests/net/csum testsuite."""
+"""A simple test for TSO."""
 
 import fcntl
 import socket