ARMV7: S5P: serial: support the s5pc210

This patch is for s5pc210 support.
Due to the resigter of baudrate is changed from slot to value,
add both of them to uart structure.

Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>