Bluetooth: Fix sending incorrect LE CoC PDU in BT_CONNECT2 state

For LE CoC L2CAP servers we don't do security level elevation during the
BT_CONNECT2 state (instead LE CoC simply sends an immediate error
response if the security level isn't high enough). Therefore if we get a
security level change while an LE CoC channel is in the BT_CONNECT2
state we should simply do nothing.

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