fs: annotate ->poll() instances

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/pipe.c b/fs/pipe.c
index 6d98566..a449ca0 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -515,10 +515,10 @@ static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 }
 
 /* No kernel lock held - fine */
-static unsigned int
+static __poll_t
 pipe_poll(struct file *filp, poll_table *wait)
 {
-	unsigned int mask;
+	__poll_t mask;
 	struct pipe_inode_info *pipe = filp->private_data;
 	int nrbufs;