arm64: dts: mediatek: mt8192: Enable cros-ec-spi as wake source

The cros_ec driver currently assumes that cros-ec-spi compatible device
nodes are a wakeup-source even though the wakeup-source property is not
defined.

Some Chromebooks use a separate wake pin, while others overload the
interrupt for wake and IO. With the current assumption, spurious wakes
can occur on systems that use a separate wake pin. It is planned to
update the driver to no longer assume that the EC interrupt pin should
be enabled for wake.

Add the wakeup-source property to all cros-ec-spi compatible device
nodes to signify to the driver that they should still be a valid wakeup
source.

Signed-off-by: Mark Hasemeyer <markhas@chromium.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20240102140734.v4.11.Ibd330d26a00f5e219a7e448452769124833a9762@changeid


Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>