Bluetooth: HCI: Fix tracking of advertisement set/instance 0x00

Bluetooth: HCI: Fix tracking of advertisement set/instance 0x00

This fixes the state tracking of advertisement set/instance 0x00 which
is considered a legacy instance and is not tracked individually by
adv_instances list, previously it was assumed that hci_dev itself would
track it via HCI_LE_ADV but that is a global state not specifc to
instance 0x00, so to fix it a new flag is introduced that only tracks the
state of instance 0x00.

Fixes: 1488af7b8b5f ("Bluetooth: hci_sync: Fix hci_resume_advertising_sync")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>