msm: mdss: disable dynamic clock gating for 8909

On 8909 platform dynamic clock gating needs to be
disabled in order to transfer dsi commands successfully.

Change-Id: I0959c2517c5c7bc6b8d251d73fb7d2d4894e1896
Signed-off-by: Sandeep Panda <spanda@codeaurora.org>