Revert "can: m_can: remove support for custom bit timing"

The timing limits specified by the Elkhart Lake CPU datasheets do not
match the defaults. Let's reintroduce the support for custom bit timings.

This reverts commit 0ddd83fb.

Link: https://lore.kernel.org/all/00c9e2596b1a548906921a574d4ef7a03c0dace0.1636967198.git.matthias.schiffer@ew.tq-group.com


Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>