mmc: msm_sdcc: enable power save mode for sd clock after voltage switch

SD3.0 compliant SD cards require voltage switching in order to
operate in UHS-I bus speed modes and as part of this voltage
switch sequence, driver is disabling the power save mode for
SD card clock and after the voltage switch is completed,
SD card clock can be put in power save mode but it is missing
as of now.

This change enables the power save mode for SD card clock
after voltage switching is completed.

Change-Id: I11fbfaafc117e4fda92a8208507fb3c8faf41181
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>