mmc: sdhci: remove support for pm_qos

pm_qos is causing race conditions in CQ mode with
power management. Removing the feature in order to
allow power management.

Change-Id: I340cd784829f389f18df6bff664337aca0f3c867
Signed-off-by: Dov Levenglick <dovl@codeaurora.org>
Signed-off-by: Konstantin Dorfman <kdorfman@codeaurora.org>