arm64: defconfig: enable ACPM protocol and Exynos mailbox

arm64: defconfig: enable ACPM protocol and Exynos mailbox

Enable the Samsung Exynos ACPM protocol and its transport layer, the
Exynos mailbox driver. Samsung Exynos platforms implement ACPM to
provide support for PMIC, clock frequency scaling, clock configuration
and temperature sensors.

Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://lore.kernel.org/r/20250207-gs101-acpm-dt-v4-4-230ba8663a2d@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250513101754.23158-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>