dt-bindings: watchdog: qcom-wdt: Make the interrupt example edge triggered

As described in the patch ("arm64: dts: qcom: sc7180: Make watchdog
bark interrupt edge triggered"), the Qualcomm watchdog timer's bark
interrupt should be configured as edge triggered.

Update the example in the bindings.

Fixes: 7c631cdff391 ("dt-bindings: watchdog: qcom-wdt: allow interrupts")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20231106144335.v2.9.Ie30c1d3f780666f6906fd2fd7c437632c229d987@changeid
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>