dt-bindings: clock: Add X1000 bindings.

Add the clock bindings for the X1000 Soc from Ingenic.

Signed-off-by: Zhou Yanjie <zhouyanjie@zoho.com>
Link: https://lkml.kernel.org/r/1573378102-72380-2-git-send-email-zhouyanjie@zoho.com


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