Bluetooth: hci_event: Set QoS encryption from BIGInfo report

On a Broadcast Sink, after synchronizing to the PA transimitted by a
Broadcast Source, the BIGInfo advertising reports emitted by the
Controller hold the encryption field, which indicates whether the
Broadcast Source is transmitting encrypted streams.

This updates the PA sync hcon QoS with the encryption value reported
in the BIGInfo report, so that this information is accurate if the
userspace tries to access the QoS struct via getsockopt.

Fixes: 1d11d70d ("Bluetooth: ISO: Pass BIG encryption info through QoS")
Signed-off-by: Iulia Tanasescu <iulia.tanasescu@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>