can: dev: add struct data_bittiming_params to group FD parameters

can: dev: add struct data_bittiming_params to group FD parameters

This is a preparation patch for the introduction of CAN XL.

CAN FD and CAN XL uses similar bittiming parameters. Add one level of
nesting for all the CAN FD parameters. Typically:

  priv->can.data_bittiming;

becomes:

  priv->can.fd.data_bittiming;

This way, the CAN XL equivalent (to be introduced later) would be:

  priv->can.xl.data_bittiming;

Add the new struct data_bittiming_params which contains all the data
bittiming parameters, including the TDC and the callback functions.

This done, update all the CAN FD drivers to make use of the new
layout.

Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://patch.msgid.link/20250501171213.2161572-2-mailhol.vincent@wanadoo.fr
[mkl: fix rcar_canfd]
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>