msm: mdss: update mdss_mdp_clk ctrl for obsolete input parameter

Starting patch I0328e156d5c0b42822f0f81aa0a8195159a1eeb7,
"mdss: display: add dynamic mdp clock control for smart panel", 2nd
argument of mdss_mdp_clk_ctrl is not used. Update implementation to
avoid passing obsolete input parameter.

Change-Id: Id9626b8a3e030e787085b257c618fd7e41d5b35a
Signed-off-by: Ujwal Patel <ujwalp@codeaurora.org>