can: bittiming: apply NL_SET_ERR_MSG() to can_calc_bittiming()

can: bittiming: apply NL_SET_ERR_MSG() to can_calc_bittiming()

When CONFIG_CAN_CALC_BITTIMING is disabled, the can_calc_bittiming()
functions can not be used and the user needs to provide all the
bittiming parameters.

Currently, can_calc_bittiming() prints an error message to the kernel
log. Instead use NL_SET_ERR_MSG() to make it return the error message
through the netlink interface so that the user can directly see it.

Signed-off-by: Vincent Mailhol <mailhol@kernel.org>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://patch.msgid.link/20251126-canxl-v8-2-e7e3eb74f889@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>