mmc: sdhci-msm: Disable SD Card's Clock Scaling

Disable the SD card's clock scaling temporarily.
The SD card's clock scaling is not functioning properly.
The issue is the SD card's mmc_deferred_scaling() tries to claim
the mmc's host using mmc_claim_host() without providing the
mmc_ctx context. When the mmc host's is also claimed by the
mmc_get_card() in another context, it may result in a hang.
Disable the SD card clock scaling feature until we find a
clean solution.

Change-Id: I7b53f351a2597057f3cf9d0c31ac35dd4e8fc042
Signed-off-by: Bao D. Nguyen <nguyenb@codeaurora.org>