SD clock should be disabled for clock value 0. It's not
right to just return. This may cause failure of signal
voltage switching.
Signed-off-by: NYangbo Lu <yangbo.lu@nxp.com>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>