msm: mdss: Fix gamma correction config for disable cases

Previously, gamma correction dirty bit is not properly set for
all the use cases, which is causing the disable ioctl for gamma
correction to fail. This change fixes the issue in disable ioctl.

Change-Id: I4901c05d305577857862f6b5316fa59ececcc842
Signed-off-by: Ping Li <pingli@codeaurora.org>
Signed-off-by: Lei Zhou <leizhou@codeaurora.org>