switch debugfs to umode_t

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/relay.h b/include/linux/relay.h
index 14a86bc..a822fd7 100644
--- a/include/linux/relay.h
+++ b/include/linux/relay.h
@@ -144,7 +144,7 @@
 	 */
 	struct dentry *(*create_buf_file)(const char *filename,
 					  struct dentry *parent,
-					  int mode,
+					  umode_t mode,
 					  struct rchan_buf *buf,
 					  int *is_global);