f2fs: introduce f2fs_has_xattr_block for better readability

This patch introduces a help function f2fs_has_xattr_block for better
readability.

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index c0fae3e..d496d16 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -836,7 +836,7 @@
 	SetPageUptodate(page);
 	set_page_dirty(page);
 
-	if (ofs == XATTR_NODE_OFFSET)
+	if (f2fs_has_xattr_block(ofs))
 		F2FS_I(dn->inode)->i_xattr_nid = dn->nid;
 
 	dn->node_page = page;
@@ -1532,7 +1532,7 @@
 
 	recover_inline_xattr(inode, page);
 
-	if (ofs_of_node(page) != XATTR_NODE_OFFSET)
+	if (!f2fs_has_xattr_block(ofs_of_node(page)))
 		return false;
 
 	/* 1: invalidate the previous xattr nid */