ARM: S3C2443: Change to using plat-samsung clksrc-clk implementation

The S3C2443 clock code could easily make use of the clksrc implementation
in plat-samsung for many of the clocks. Make the clocks that easily move
to clksrc-clk over, update any initialisation and remove the old register
definitions from the header file (it is only being used once).

Signed-off-by: Ben Dooks <ben-linux@fluff.org>