Bluetooth: Fix checking the wrong flag when accepting a socket

Most probably a typo, the check should have been for BT_SK_DEFER_SETUP
instead of BT_DEFER_SETUP (which right now only represents a socket
option).

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Acked-by: Andrei Emeltchenko <andrei.emeltchenko@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>