ARM: S3C24XX: move spi-s3c24xx platdata out of mach

spi.h now only contains the definition of the platform data structure
for the driver in spi-s3c24xx.c . Therefore it does not need to stay
in include/mach but can instead live in linux/spi/s3c24xx.h .

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>