Bluetooth: Fix adv_work delay

This patch fixes the adv_work delay. It should be set to ADV_
CLEAR_TIMEOUT instead of (jiffies + ADV_CLEAR_TIMEOUT) since
queue_delayed_work() receives the number of jiffies to wait
before queueing. It also removes the unnecessary cancel_delayed_
work_sync() call in case LE scan has been disabled.

Signed-off-by: Andre Guedes <andre.guedes@openbossa.org>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>