forgot a return path

Ahh, sorry, I got confused with the missing context- can you reupload this with either git-arc or -U99999, please?

full diff with context

sprkopen currently uses the fact that it's locked by Giant, so you'll probably want one spkr mutex to be taken in spkropen() and spkrclose() to be sure it's only opened by a single thread

forgot an include in last revision

Also add a mutex for ioctl/write

Make spkropen thread-safe

My previous upload was incomplete.