dt-bindings: timer: exynos4210-mct: Add compatible for ARTPEC-9 SoC

Add Axis ARTPEC-9 mct compatible to the bindings documentation.
The design for the timer is reused from previous Samsung SoCs
like exynos4210 and ARTPEC-8.

Signed-off-by: SungMin Park <smn1196@coasia.com>
Signed-off-by: Ravi Patel <ravi.patel@samsung.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250917071311.1404-1-ravi.patel@samsung.com