ARM: SAMSUNG: Add clkdev infrastructure

The struct clk definition for Samsung platforms is extended to include
a instance of struct clk_lookup and a device name. When clocks are
registered using s3c24xx_register_clock function, the dev_id, con_id
and clk members are initialized with information from the struct clk
instance and struct clk_lookup member is registered.

Signed-off-by: Thomas Abraham <thomas.ab@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>