Bluetooth: Introduce L2CAP channel flag for defer setup

The L2CAP core should not look into the socket flags to figure out the
setting of defer setup. So introduce a L2CAP channel flag that mirrors
the socket flag.

Since the defer setup option is only set in one place this becomes a
really easy thing to do.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index a27d51d..1a38ede 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -652,6 +652,7 @@
 	FLAG_FLUSHABLE,
 	FLAG_EXT_CTRL,
 	FLAG_EFS_ENABLE,
+	FLAG_DEFER_SETUP,
 };
 
 enum {