Fix USB athn(4) to be able to build on the RAMDISK. RAMDISK has SMALL_KERNEL so there is no HostAP. athn_usb_newassoc() would return if not in HostAP mode so just stub out the function and don't build the callback function for the RAMDISK.
Fix USB athn(4) to be able to build on the RAMDISK. RAMDISK has SMALL_KERNEL
so there is no HostAP. athn_usb_newassoc() would return if not in HostAP mode
so just stub out the function and don't build the callback function for
the RAMDISK.

ok deraadt@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars