target: add support to use DSI1 PLL to drive a display panel

In the current implementation, we use only DSI0 PLL to drive both
the single DSI and split DSI use cases. However, there can be use
cases where a single DSI panel needs to be driven on DSI1 controller
using DSI1 PLL. Hence, add support for using DSI1 PLL.

Change-Id: If26383c1dc14306cadfa5ad832ffbafb1557222a
12 files changed