dt-bindings: clock: amlogic: convert amlogic,gxbb-clkc.txt to dt-schema

Convert the Amlogic Clock Controller bindings to dt-schema.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://lore.kernel.org/r/20230706-b4-amlogic-bindings-convert-take2-v3-1-f63de6f12dcc@linaro.org
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>