filesystems: add missing nlink wrappers

Replace direct i_nlink updates with the respective updater function
(inc_nlink, drop_nlink, clear_nlink, inode_dec_link_count).

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c
index 25b2443..4536cd3 100644
--- a/fs/hfsplus/dir.c
+++ b/fs/hfsplus/dir.c
@@ -415,7 +415,7 @@
 	goto out;
 
 out_err:
-	inode->i_nlink = 0;
+	clear_nlink(inode);
 	hfsplus_delete_inode(inode);
 	iput(inode);
 out:
@@ -440,7 +440,7 @@
 
 	res = hfsplus_create_cat(inode->i_ino, dir, &dentry->d_name, inode);
 	if (res) {
-		inode->i_nlink = 0;
+		clear_nlink(inode);
 		hfsplus_delete_inode(inode);
 		iput(inode);
 		goto out;