switch ->mknod() to umode_t

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 19630aa..0060875 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -4596,7 +4596,7 @@
 }
 
 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
-			int mode, dev_t rdev)
+			umode_t mode, dev_t rdev)
 {
 	struct btrfs_trans_handle *trans;
 	struct btrfs_root *root = BTRFS_I(dir)->root;