ARM: at91: add clock selection parameter for at91_add_device_isi()

Add parameter and change existing call in at91sam9263_devices.c.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Olof Johansson <olof@lixom.net>