msm: mdss: always vote for ab/ib before solid fill starts on MDP3

For fill area less than half of screen size driver was not updating
ab/ib vote and assumed fudge in existing PPP vote should cover up
for solid fill bandwidth need.
Now vote for ab/ib before solid fill operation starts, irrespective of
the fill area size to prevent MDP under voting.

Change-Id: I47561f8dfd5cb28292685afc41da4a7166551fdf
Signed-off-by: Krishna Manikandan <mkrishn@codeaurora.org>