f2fs: fix wrong statistics of inline data

If we remove a file that has inline data after mount, our statistics turns to
inaccurate.

cat /sys/kernel/debug/f2fs/status
  - Inline_data Inode: 4294967295

Let's add stat_inc_inline_inode() to stat inline info of the file when lookup.

Change log from v1:
 o stat in f2fs_lookup() instead of in do_read_inode() for excluding wrong stat.
Signed-off-by: NChao Yu <chao2.yu@samsung.com>
Signed-off-by: NJaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/namei.c

@@ -207,6 +207,8 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry,
 		inode = f2fs_iget(dir->i_sb, ino);
 		if (IS_ERR(inode))
 			return ERR_CAST(inode);
+
+		stat_inc_inline_inode(inode);
 	}
 
 	return d_splice_alias(inode, dentry);