dt-bindings: Rename Ingenic CGU headers to ingenic,*.h

Tidy up a bit the tree, by prefixing all include/dt-bindings/clock/ files
related to Ingenic SoCs with 'ingenic,'.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20211016133322.40771-1-paul@crapouillou.net