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 work-around this issue, we are now
triggering the retuning of tuning circuit once clocks are ungated.

This change enables re-tuning when tuning is executed, marks tuning is
needed whenever clock is ungated and disable re-tuning when card is
no longer initialized.

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