Make sure the private data is initially NULL

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1293 42af7a65-404d-4744-a932-0658087f49c3

fs/fs_poll.c

@@ -165,6 +165,7 @@ static inline int poll_setup(FAR struct pollfd *fds, nfds_t nfds, sem_t *sem)
 
       fds[i].sem     = sem;
       fds[i].revents = 0;
+      fds[i].private = NULL;
 
       /* Set up the poll */