The CAN - USB PCAN-USB interface is able to generate one-shot frames
as well as loopback frames that it transmits starting from version 4.1
of its firmware.

This patch adds support for the one-shot and loopback functionality to
the driver, that can be activated if the embedded firmware allows it.
If the driver detects that the PCAN-USB device runs an old firmware
(< 4.1) it prints a message suggesting to contact
<support@peak-system.com> for a possible firmware update.

Link: https://lore.kernel.org/r/20210625130931.27438-3-s.grosjean@peak-system.comSigned-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>