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.

Add the wakeup-source property to all cros-ec-spi compatible device
nodes to match expected behavior.
Signed-off-by: Mark Hasemeyer <markhas@chromium.org>
Link: https://lore.kernel.org/r/20231220165423.v2.6.I06b059021de1bf6103e60a73211f078f2af75d17@changeidSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>