ARM: dts: vt8500: list all four timer interrupts

ARM: dts: vt8500: list all four timer interrupts

VIA/WonderMedia SoC timer can generate up to four interrupts corresponding
to four timer match registers (firing when the 32-bit freerunning clock
source counter matches either of the match registers, respectively).

List all four interrupts in device trees.

This also enables the system event timer to use a match register other
than 0, which can then in turn be used as a system watchdog (watchdog
function is not available on other channels)

Signed-off-by: Alexey Charkov <alchark@gmail.com>
Link: https://lore.kernel.org/r/20250507-vt8500-timer-updates-v2-4-65e5d1b0855e@gmail.com
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>