dt-bindings: clock: Document SM8150 rpmh-clock compatible

Document the SM8150 rpmh-clock compatible for rpmh clock controller
found on SM8150 platforms.

Signed-off-by: Vinod Koul <vkoul@kernel.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lkml.kernel.org/r/20190826173120.2971-4-vkoul@kernel.org


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