msm: mdss: fix six zone saturation mask

The mask for setting the six zone LUT is incorrect. This
change fixes the mask to make sure all data is written to
the hardware.

Change-Id: Ic8cb82cbf9d34d857c71c03decc8b64f3a3e9699
Signed-off-by: Benet Clark <benetc@codeaurora.org>