evdev: Add an internal device suspend / resume notification system

evdev: Add an internal device suspend / resume notification system

We have the ability for a device to form a link to another device through the
device_added / device_removed callbacks. A device having such a link to
another device may also want to know when that other device is disabled /
enabled (suspended / resumed). So add a notification mechanism for this too.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>