dt-bindings: clock: add support for DSI CPHY clocks

Add CPHY specific clocks to support MIPI DSI CPHY on
Lahaina hardware. Add the relevant clock bindings.

Change-Id: If7dd806e6427b65427d5999bb9ccda7098ec610b
Signed-off-by: Chandan Uddaraju <chandanu@codeaurora.org>
Signed-off-by: Yuan Zhao <yzhao@codeaurora.org>