Revert "msm: mdss: Increase the cnoc clock rate"

This patch will increase the cnoc clock rate whenever MDP is on, which
is not necessary. The desired implementation is to increase the cnoc
clock rate when hist LUT are updated.
This reverts commit 61223f37af38d14f56ee67f823cb3eda52a81f93.

Change-Id: I8394bf33175b050567f6c3ada586cb4f1d3c4d7e
Signed-off-by: Ping Li <quicpingli@codeaurora.org>