Bluetooth: Fix ATT socket backwards compatibility with user space

Old user space versions bind the Attribute Protocol socket to
BDADDR_BREDR when they should be using BDADDR_LE_PUBLIC or
BDADDR_LE_RANDOM. The kernel recently introduced stricter checks on the
socket parameters but we need to punch this hole for old user space
versions to keep them working.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>