bluetooth: a2dp: improve the stream l2cap release

When signal l2cap is disconnected, use `release_work` to release the
related stream l2cap connections. When releasing the sep's stream l2cap,
use `delay_work` to check the stream l2cap disconnecting result.
Move the stream l2cap disconnecting callback to sep because the chan is
in sep, then use this callback to indicate the sep stream chan is
released and sep is idle.

Signed-off-by: Mark Wang <yichang.wang@nxp.com>
4 files changed