Bluetooth: Reject LE CoC commands when the feature is not enabled

Since LE CoC support needs to be enabled through a module option for now
we need to reject any related signaling PDUs in addition to rejecting
the creation of LE CoC sockets (which we already do).

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