msm: clock-8610: Add support for the DSI panel clocks

The DSI PLLs are controlled by the display driver
on the 8x10. Add the necessary support to the clock
driver to interface with the PLL code.

Change-Id: I4ba4c90107016e5bb14eb24b767f824d4d955d0f
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>