ARM: S3C24XX: remove obsolete s3c2412 specific dma settings

The s3c2412 dma init contained code to handle dma-direction specific
settings. As now all s3c2412-dma-channels are direction-independent this
is not needed anymore.

As the s3c2412 also was the only user of this, it can go away completely.

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