mmc: msm_sdcc: fix clock gating handling using pwrsave control bit

SDCC controller provides the PWRSAVE control bit to automatically
disable the clock to card when there is no activity with card. SDCC
host controller driver always enables this feature but few SDIO
cards may require the clocks to be always running (even during
inactivity period) to raise the interrupt notification to host so
for such cards, enabling PWRSAVE fature may cause functional failures.

This change checks whether it is ok to gate the card clock before
enabling the PWRSAVE feature.

Change-Id: If36a6a20d59aeb555ece2a6959ab5407f90c787c
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>