msm: camera: sensor: Round the clock rate before setting

clock has different rates. Once desired clock rate is calculated,
call clk_roundrate() to get supported clk rate and set it using
clk_setrate().So we rounded the desired clock rate to get the
supported value for the corresponding modules.

Change-Id: I8e35626dd39e60cc57711bf16cd3c655471ea64c
Signed-off-by: Cherian Deepak <dcheri@codeaurora.org>