locks: fix fcntl_setlease/getlease return when !CONFIG_FILE_LOCKING

Currently they both just return 0. Fix them to return more appropriate
values instead.

For better or worse, most places in the kernel return -EINVAL when
leases aren't available. -ENOLCK would probably have been better, but
let's follow suit here in the case of F_SETLEASE.

In the F_GETLEASE case, just return F_UNLCK since we know that no
lease will have been set.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

include/linux/fs.h

@@ -1008,12 +1008,12 @@ static inline int fcntl_setlk64(unsigned int fd, struct file *file,
 #endif
 static inline int fcntl_setlease(unsigned int fd, struct file *filp, long arg)
 {
-	return 0;
+	return -EINVAL;
 }
 
 static inline int fcntl_getlease(struct file *filp)
 {
-	return 0;
+	return F_UNLCK;
 }
 
 static inline void locks_init_lock(struct file_lock *fl)