ARM: SAMSUNG: Move S3C24XX header files to plat-samsung

This patch moves header files from plat-s3c24xx to plat-samsung to
remove plat-s3c24xx directory to make one plat-samsung directory for
Samsung SoCs. And this patch includes fixing coding style, too.

Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>