Bluetooth: Fix indicating discovery state when canceling inquiry

When inquiry is canceled through the HCI_Cancel_Inquiry command there is
no Inquiry Complete event generated. Instead, all we get is the command
complete for the HCI_Inquiry_Cancel command. This means that we must
call the hci_discovery_set_state() function from the respective command
complete handler in order to ensure that user space knows the correct
discovery state.

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