msm: mdss: Correct HDMI interface polarity for different resolutions.

For HDMI, hsync and vsync polarity for resolution height greater than or
equal to 720 lines is active high. And for resolution height less
than 720 lines is active low. Program the these settings correctly
for mdp's hdmi interface.

Change-Id: I1a8889662f55676c13dfa8b7172bf7bcf7351cf5
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>