can: add Renesas R-Car CAN driver

Add support for the CAN controller found in Renesas R-Car SoCs.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --cc drivers/net/can/Kconfig
Simple merge

diff --cc drivers/net/can/Makefile
Simple merge

diff --cc drivers/net/can/rcar_can.c
Simple merge

diff --cc include/linux/can/platform/rcar_can.h
Simple merge