dt-bindings: mailbox: qcom,apcs-kpss-global: use fallbacks for few variants

dt-bindings: mailbox: qcom,apcs-kpss-global: use fallbacks for few variants

Rework the compatibles of IPQ8074, SC7180, SC8180X and SM8150 as
compatible devices (same from Linux driver point of view).  This allows
smaller of_device_id table in the Linux driver and smaller
allOf:if:then: constraints.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>