dt-bindings: clock: Fix qcom,dispcc bindings for sdm845/sc7180

dt-bindings: clock: Fix qcom,dispcc bindings for sdm845/sc7180

The qcom,dispcc bindings had a few problems with them:

1. They didn't specify all the clocks that dispcc is a client of.
   Specifically on sc7180 there are two clocks from the DSI PHY and
   two from the DP PHY.  On sdm845 there are actually two DSI PHYs
   (each of which has two clocks) and an extra clock from the gcc.
   These all need to be specified.

2. The sdm845.dtsi has existed for quite some time without specifying
   the clocks.  The Linux driver was relying on global names to match
   things up.  While we should transition things, it should be noted
   in the bindings.

3. The names used the bindings for "xo" and "gpll0" didn't match the
   names that QC used for these clocks internally and this was causing
   confusion / difficulty with their code generation tools.  Switched
   to the internal names to simplify everyone's lives.  It's not quite
   as clean in a purist sense but it should avoid headaches.  This
   officially changes the binding, but that seems OK in this case.

Also note that I updated the example.

Fixes: 5d28e44ba630 ("dt-bindings: clock: Add YAML schemas for the QCOM DISPCC clock bindings")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lkml.kernel.org/r/20200203103049.v4.2.I0c4bbb0f75a0880cd4bd90d8b267271e2375e0d0@changeid
Signed-off-by: Stephen Boyd <sboyd@kernel.org>