msm: mdss: Increase Bandwidth fudge factor for msm8916.

With current fudge factor of 1.2, underruns are observed
in some use cases. Fix the issue by increasing
fudge factor to 2.

Change-Id: Idd6c6c9e27957243a1d78ae33b04d5615a04126c
Signed-off-by: Vishnuvardhan Prodduturi <vproddut@codeaurora.org>