Bluetooth: Fix crash when using new BT_PHY option

This fixes the invalid check for connected socket which causes the
following trace due to sco_pi(sk)->conn being NULL:

RIP: 0010:sco_sock_getsockopt+0x2ff/0x800 net/bluetooth/sco.c:966

L2CAP has also been fixed since it has the same problem.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>