dt-bindings: clock: uniphier: Add clock binding for SoC-glue

Update binding document for clocks implemented in SoC-glue.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Link: https://lore.kernel.org/r/1634000035-3114-5-git-send-email-hayashi.kunihiko@socionext.com


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