ARM: S5PC100: UART and Serial

Serial driver of S5PC100 is the same as S3C6400, so S5PC100 shares the serial
driver with S3C6400. Uart driver is copied from plat-s3c64xx to plat-s5pc1xx,
as I do not use plat-s3c64xx directory.

Signed-off-by: Byungho Min <bhmin@samsung.com>
[ben-linux@fluff.org: title fixup]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>