Bluetooth: Start channel move when socket option is changed

Channel moves are triggered by changes to the BT_CHANNEL_POLICY
sockopt when an ERTM or streaming-mode channel is connected.

Moves are only started if enable_hs is true.

Signed-off-by: Mat Martineau <mathewm@codeaurora.org>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>