->poll() methods should return __poll_t

The most common place to find POLL... bitmaps: return values
of ->poll() and its subsystem counterparts.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

include/linux/net.h

@@ -147,7 +147,7 @@ struct proto_ops {
 	int		(*getname)   (struct socket *sock,
 				      struct sockaddr *addr,
 				      int *sockaddr_len, int peer);
-	unsigned int	(*poll)	     (struct file *file, struct socket *sock,
+	__poll_t	(*poll)	     (struct file *file, struct socket *sock,
 				      struct poll_table_struct *wait);
 	int		(*ioctl)     (struct socket *sock, unsigned int cmd,
 				      unsigned long arg);