mmc: fsl_esdhc_imx: Fix clock disable issue

The SD clock disable is wrapped by MMC_SUPPORTS_TUNING. So it
only works when UHS is enabled. However, in SD initialization the
power cycle does not depends on UHS. But the power cycle needs
disable the SD clock before power down.
So this causes a problem when UHS is not enabled. Some cards can't
become ready (ACMD14 timeout) due to the clock is enabled during
power cycle.

Signed-off-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>