ARM: S3C24XX: remove legacy clock code

With the move to the common clock framework completed for s3c2410, s3c2440
and s3c2442, the legacy clock code for these machines can go away too.

This also includes the legacy dclk code, as all legacy users are converted.

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