ARM: mach-imx/mx27_3ds: Do not annotate the chip select as internal

On the i.MX SPI driver the chipselect pins can be of the following types:

- internal: when the chipselect pin is used as a dedicated CS pin of the CSPI controller
- GPIO: a generic GPIO can be used as a chipselect funtion

On the mx27_3ds the SPI2 chip select is a GPIO, so don't annotate 'internal' in the chip select
definition.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>