Merge patch "Documentation: networking: document ISO 15765-2"

Francesco Valla <valla.francesco@gmail.com> says:

While the in-kernel ISO 15765-2 (ISO-TP) stack is fully functional and
easy to use, no documentation exists for it.

This patch adds such documentation, containing the very basics of the
protocol, the APIs and a basic example.

Link: https://lore.kernel.org/all/20240501092413.414700-1-valla.francesco@gmail.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>