msm: mdss: mdp clock changes for msm8909

mdp clocks on 8909 is similar to 8916. Add changes to
take care of this. Also remove dsi_clk and lcdc_clk as
they are not needed for 8909.

Change-Id: I17d9268d99681bb354f2e1803db5ddb38ba97afa
Signed-off-by: Shivaraj Shetty <shivaraj@codeaurora.org>