clk: qcom: mdss: add support for 10nm DSI PLL shadow clock

Add support for 10nm DSI PLL shadow clocks, which will be
used during dynamic dsi clock switch and dfps feature.

Change-Id: Ib61bc5dcb5304bc1e3c7568c1419737580da3c88
Signed-off-by: Sandeep Panda <spanda@codeaurora.org>