dt-bindings: clock: Add support for MSM8992/4 MMCC

Document the multimedia clock controller found on MSM8992/4.

Signed-off-by: Konrad Dybcio <konrad.dybcio@somainline.org>
Link: https://lore.kernel.org/r/20210618111435.595689-1-konrad.dybcio@somainline.org


Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>