can: m_can: remove support for custom bit timing, take #2

Now when Intel Elkhart Lake uses again common bit timing and there are
no other users for custom bit timing, we can bring back the changes
done by the commit 0ddd83fb ("can: m_can: remove support for
custom bit timing").

This effectively reverts commit ea768b2f ("Revert "can: m_can:
remove support for custom bit timing"") while taking into account
commit ea22ba40 ("can: m_can: make custom bittiming fields const")
and commit 7d4a101c ("can: dev: add sanity check in
can_set_static_ctrlmode()").

Link: https://lore.kernel.org/all/20220512124144.536850-2-jarkko.nikula@linux.intel.com


Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>