msm: mdss: fix TCXO issue on 8909MTP

In MSM8909 video mode panel, mdss clocks were not turned off
which lead to TCXO test failures. Make sure that the
clock disable api is called for video mode panel so that
clocks are turned off during suspend.

Change-Id: I5c466090a798c63e7c14f88e10df21de5cb60fbf
Signed-off-by: Raghavendra Ambadas <rambad@codeaurora.org>