remove struct 's3c24xx_uart_clksrc' and all uses of it

With clkdev based clock lookup added to samsung serial driver, the use
of 'struct s3c24xx_uart_clksrc' to supply clock names in platform
data is removed from all the Samsung platform code.

Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Ramax Lo <ramaxlo@gmail.com>
Cc: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
å