msm: mdss: Move PP programming after mdp wait for ping pong done

To ensure PP registers are not programming in the middle of the
frame transfer moving PP programming to after wait4pingpong
for command mode panel devices.

Change-Id: Ie639a26543e2f20b61d6dfc73b3bcbd6a43b24be
Signed-off-by: Sravan Kumar D.V.N <sravank1@codeaurora.org>
Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>