Bluetooth: Fix allowing initiating pairing when not pairable

When we're not pairable we should still allow us to act as initiators
for pairing, i.e. the HCI_PAIRABLE flag should only be affecting
incoming pairing attempts. This patch fixes the relevant checks for the
hci_io_capa_request_evt() and hci_pin_code_request_evt() functions.

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