can: canxl: support Remote Request Substitution bit access

The Remote Request Substitution bit is a dominant bit ("0") in the CAN
XL frame. As some CAN XL controllers support to access this bit a new
CANXL_RRS value has been defined for the canxl_frame.flags element.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://patch.msgid.link/20250124142347.7444-1-socketcan@hartkopp.net


Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>