nilfs2: use mark_buffer_dirty to mark btnode or meta data dirty

This replaces nilfs_mdt_mark_buffer_dirty and nilfs_btnode_mark_dirty
macros with mark_buffer_dirty and gets rid of nilfs_mark_buffer_dirty,
an own mark buffer dirty function.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/alloc.c b/fs/nilfs2/alloc.c
index f768448..eed4d7b 100644
--- a/fs/nilfs2/alloc.c
+++ b/fs/nilfs2/alloc.c
@@ -489,8 +489,8 @@
 void nilfs_palloc_commit_alloc_entry(struct inode *inode,
 				     struct nilfs_palloc_req *req)
 {
-	nilfs_mdt_mark_buffer_dirty(req->pr_bitmap_bh);
-	nilfs_mdt_mark_buffer_dirty(req->pr_desc_bh);
+	mark_buffer_dirty(req->pr_bitmap_bh);
+	mark_buffer_dirty(req->pr_desc_bh);
 	nilfs_mdt_mark_dirty(inode);
 
 	brelse(req->pr_bitmap_bh);
@@ -527,8 +527,8 @@
 	kunmap(req->pr_bitmap_bh->b_page);
 	kunmap(req->pr_desc_bh->b_page);
 
-	nilfs_mdt_mark_buffer_dirty(req->pr_desc_bh);
-	nilfs_mdt_mark_buffer_dirty(req->pr_bitmap_bh);
+	mark_buffer_dirty(req->pr_desc_bh);
+	mark_buffer_dirty(req->pr_bitmap_bh);
 	nilfs_mdt_mark_dirty(inode);
 
 	brelse(req->pr_bitmap_bh);
@@ -683,8 +683,8 @@
 		kunmap(bitmap_bh->b_page);
 		kunmap(desc_bh->b_page);
 
-		nilfs_mdt_mark_buffer_dirty(desc_bh);
-		nilfs_mdt_mark_buffer_dirty(bitmap_bh);
+		mark_buffer_dirty(desc_bh);
+		mark_buffer_dirty(bitmap_bh);
 		nilfs_mdt_mark_dirty(inode);
 
 		brelse(bitmap_bh);