msm_fb: display: calculate mdp clock including borderfill pipe

For hdmi case, mdp clock calculation needs including borderfill
pipe to prevent dtv underrun while system is in suspend.

Crs-fixed: 449027
Change-Id: I98789343317d5cfdf1f56e496cecb4dd663c907f
Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>