dt-bindings: msm: dsi-controller-main: Document clocks on a per compatible basis

Each compatible has a different set of clocks which are associated with it.
Add in the list of clocks for each compatible. We will need to fixup the
order of clock declarations in a separate patch also.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>