ARM: imx23-olinuxino: Add spi support

imx23-olinuxino board has spi pins exposed on external connector.
This patch add spi support.

Signed-off-by: Fadil Berisha <f.koliqi@gmail.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>