Add definition for the clock controller of the CV1800 series SoC.

For CV181X, it has a clock that CV180X does not have. To avoid misuse,
also add a compatible string to identify CV181X series SoC.
Signed-off-by: Inochi Amaoto <inochiama@outlook.com>
Link: https://github.com/milkv-duo/duo-files/blob/main/hardware/CV1800B/CV1800B-CV1801B-Preliminary-Datasheet-full-en.pdfReviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/IA1PR20MB49535E448097F6FFC1218C39BB90A@IA1PR20MB4953.namprd20.prod.outlook.comSigned-off-by: Stephen Boyd <sboyd@kernel.org>