mmc: core: retune after un-gating the clocks

We have seen that host controller's clock tuning circuit may go out of sync
if controller clocks are gated. To workaround this issue, we are now
triggering the retuning of tuning circuit once clocks are ungated.

Change-Id: Id2db1cb4829fbb1af4f8c4e463d1e16c0f45e590
Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>