clk: qcom: mdss: Fix flicker issue at early boot of kernel

During early boot the pll registers are reconfigured during handoff,
which is causing flicker while preparing dsi hs clocks.
To avoid momentary flicker, skip writing to pll registers during handoff.

Change-Id: I48d5cb88dec407ff872a421d15357d353498a485
Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>
Signed-off-by: Raghavendra Ambadas <rambad@codeaurora.org>