arm64: dts: exynos: add pwm node for exynosautov9-sadk

Add pwm node to support fan on exynosautov9-sadk board.
PWM channel 3 of ExynosAutov9 is connected to fan for SoC cooling
in SADK board.

Signed-off-by: Jaewon Kim <jaewon02.kim@samsung.com>
Link: https://lore.kernel.org/r/20230718062200.79306-3-jaewon02.kim@samsung.com


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>