can: sja1000: Add support for CAN_CTRLMODE_PRESUME_ACK

SJA1000 has a self test mode (STM) which does not require
acknowledgement for the successful message transmission. In this mode a
node test is possible without any other active node on the bus.

This patch adds a possibility to set STM for SJA1000 controller through
specifying the corresponding CAN_CTRLMODE_PRESUME_ACK netlink flag.

Signed-off-by: Nikita Edward Baruzdin <nebaruzdin@gmail.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>