dt-bindings: clock: jz4725b-cgu: Add UDC PHY clock

Add macro for the UDC PHY clock of the JZ4725B.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>