dt-bindings: clock: Add jz4770-cgu.h header

dt-bindings: clock: Add jz4770-cgu.h header

This will be used from the devicetree bindings to specify the clocks
that should be obtained from the jz4770-cgu driver.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Maarten ter Huurne <maarten@treewalker.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/18481/
Signed-off-by: James Hogan <jhogan@kernel.org>