Assigning 2 to "renesas,can-clock-select" tricks the driver into
registering the CAN interface, even though we don't want that.
This patch improves one of the checks to prevent that from happening.
Fixes: 9f8e8b0ca7ae89af ("can: rcar_can: support all input clocks") Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com> Signed-off-by: Chris Paterson <Chris.Paterson2@renesas.com> Reviewed-by: Simon Horman <horms+renesas@verge.net.au> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>