Throw an exception in RoR api on no-pin case

If the device doesn't have a pin, the current RoR preparation will
go through; but the lskf capture event won't happen. In order not
to confuse the caller, throw an exception instead in the no-pin
case.

Bug: 170664917
Test: remove pin, request RoR with adb shell
Change-Id: Ib04c629234b71e3f6cb36bdfe47759a715a69146