ARM: S3C24XX: Consolidate Simtec extensions

The Simtec extension didn't follow a specific naming scheme for files
and config options until now. This distributed the files throughout
the whole mach-s3c24xx directory.

This patch fixes the naming of files and option names and also creates
a simtec.h header instead of using many one-liners.

As the plat/audio-simtec.h only contains the platform-data struct now,
it can also move to include/sound in a later patch.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>