ARM: dts: add spi nodes for the atmel boards

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
[wenyou.yang@atmel.com: added spi nodes for the sam9263ek, sam9g20ek, sam9m10g45ek and sam9n12ek boards]
[wenyou.yang@atmel.com: submit the patch]
Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>