S5P: add set_mmc_clk for external clock control

This patch added set_mmc_clk for external clock control.

c210 didn't support host clock control.
So We need external_clock_control function for c210.

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
7 files changed