dt-bindings: watchdog: qcom-wdt: do not allow fallback alone

The compatible "qcom,kpss-wdt" is too generic and should not be used
alone.  Mark it as deprecated when not prepended by specific compatible.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20221212163532.142533-2-krzysztof.kozlowski@linaro.org


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>