Bluetooth: iso: Allow BIG re-sync

Bluetooth: iso: Allow BIG re-sync

A Broadcast Sink might require BIG sync to be terminated and
re-established multiple times, while keeping the same PA sync
handle active. This can be possible if the configuration of the
listening (PA sync) socket is reset once all bound BISes are
established and accepted by the user space:

1. The DEFER setup flag needs to be reset on the parent socket,
to allow another BIG create sync procedure to be started on socket
read.

2. The BT_SK_BIG_SYNC flag needs to be cleared on the parent socket,
to allow another BIG create sync command to be sent.

3. The socket state needs to transition from BT_LISTEN to BT_CONNECTED,
to mark that the listening process has completed and another one can
be started if needed.

Signed-off-by: Iulia Tanasescu <iulia.tanasescu@nxp.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>