clk: samsung: exynosautov9: add cmu_core clock support

Add CMU_CORE clock which represents Core BUS clocks. The source clocks
of this CMU block are oscclk or dout_clkcmu_core_bus. Thus, two source
clocks should be provided via device tree. All the gate clocks are
defined as CLK_IS_CRITICAL because they control(gate/ungate) core bus
clocks but not been assigned to any drivers.

Signed-off-by: Chanho Park <chanho61.park@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Link: https://lore.kernel.org/r/20220504075154.58819-5-chanho61.park@samsung.com