can: sja1000: platform: use devm_* APIs

Simplify probe and remove functions by converting most of the resources
to use devm_* APIs.

Signed-off-by: Florian Vaussard <florian.vaussard@epfl.ch>
Tested-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>