HID: Kysona: Add periodic online check

This patch adds a periodic online check at the same interval the battery
status gets requested.
With this change the driver can detect when the mouse is turned off while
the dongle is still plugged in.

Tested with a Kysona M600 V-HUB Special Edition.

Signed-off-by: Lode Willems <me@lodewillems.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>