clk: qcom: videocc: Remove sleep clock for SM6150

As the sleep clock is defined from the device tree, remove all instances of
the sleep clock from the video code. Also update the clock indexes
accordingly.

Change-Id: I225403f3c14bfc96d564a8ad2ab9520b347a7f50
Signed-off-by: Taniya Das <tdas@codeaurora.org>