msm: mdss: reduce rotator fps for high resolution

For 4k video playback, video only expects to decode
at 30fps for current target. This means that
rotator is only expected to run at 30fps for 4k
resolutions, this change considers this for the
rotator bandwidth calculation in order to optimize
the bandwith vote.

Change-Id: I416a5f2bda00bdd962fa7d26fba2ed19f4247d81
Signed-off-by: Ingrid Gallardo <ingridg@codeaurora.org>