clk: qcom: mdss: update dsi 12nm clock driver

Add 12nm clock to mdss clocks. Fix regmap parameters.
Move clock commit to set_rate. Set divider values to
registers instead of setting them during prepare call.

Change-Id: I4eec349875e392dd707d0ac93f906428ca4b97e3
Signed-off-by: Venkata Prahlad Valluru <vvalluru@codeaurora.org>
Signed-off-by: Nirmal Abraham <nabrah@codeaurora.org>