Commit 9ee51f01 (tty: serial/samsung: make register definitions
global) removed the S3C2410_PA_UARTX defines that the newly merged
s3c2416 dt support still expected.

So update mach-s3c2416-dt.c to use the S3C24XX_PA_UART constant until
we have support for the common clock framework the the s3c2416-dt.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>