msm: mdss: Add overlay source side histogram LUT

Allow for overlay API to set histogram LUT. Currently multiple pipes can be
specified by the overlay requests; however, only the pipe that was
allocated by the request will have the histogram LUT applied to it.

Change-Id: Ifebca3fd3cc03e4ed9df638555da1b6d850e070b
Signed-off-by: Carl Vanderlip <carlv@codeaurora.org>