Bluetooth: Fix parameter order of hci_get_route

The actual parameter order of hci_get_route is (dst, src) and not (src,
dst). All current callers use the right order but the header file shows
the parameters in the wrong order.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>