can: rcar: add SPDX identifiers to Kconfig and Makefile

This patch adds SPDX-License-Identifier to Kconfig and Makefile.
Signed-off-by: NKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Acked-by: NRamesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/rcar/Kconfig

+# SPDX-License-Identifier: GPL-2.0
 config CAN_RCAR
 	tristate "Renesas R-Car CAN controller"
 	depends on ARCH_RENESAS || ARM

drivers/net/can/rcar/Makefile

+# SPDX-License-Identifier: GPL-2.0
 #
 #  Makefile for the Renesas R-Car CAN & CAN FD controller drivers
 #