Bluetooth: hci_core: Fix tracking of periodic advertisement

Bluetooth: hci_core: Fix tracking of periodic advertisement

Periodic advertising enabled flag cannot be tracked by the enabled
flag since advertising and periodic advertising each can be
enabled/disabled separately from one another causing the states to be
inconsistent when for example an advertising set is disabled its
enabled flag is set to false which is then used for periodic which has
not being disabled.

Fixes: eca0ae4aea66 ("Bluetooth: Add initial implementation of BIS connections")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>