at91sam9263: add at91_can device to generic device definition

This patch adds the device definition for the at91_can device to
the generic device definiton file for the at91sam9263.

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>
Signed-off-by: David S. Miller <davem@davemloft.net>