spi/s3c64xx: Use core cs_gpio field
spi/s3c64xx: Use core cs_gpio field

Rather than using the driver custom platform data to store the chip select
GPIO use the cs_gpio field provided by the SPI core, supporting future
refectoring.

Signed-off-by: Mark Brown <b51b9a92386687a9ac927cebfa0f978adeb8cea5@linaro.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs