at91sam9263ek: activate at91 CAN controller

This patch activates the at91 CAN controller for the at91sam9263ek
development board.

Signed-off-by: Hans J. Koch <hjk@linutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Acked-by: Andrew Victor <linux@maxim.org.za>
Signed-off-by: David S. Miller <davem@davemloft.net>