exynos: Drop CONFIG_CLK_*

We only set one of these values ever at this point, so remove dead code.

Cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Minkyu Kang <mk7.kang@samsung.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>