cros_ec: Don't signal wake event for non-wake host events

The subset of wake-enabled host events is defined by the EC, but the EC
may still send non-wake host events if we're in the process of
suspending. Get the mask of wake-enabled host events from the EC and
filter out non-wake events to prevent spurious aborted suspend
attempts.

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Benson Leung <bleung@chromium.org>