nilfs2: convert nilfs_mdt_submit_block to use a folio

Saves two calls to compound_head().

Link: https://lkml.kernel.org/r/20231114084436.2755-14-konishi.ryusuke@gmail.comSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/nilfs2/mdt.c

@@ -158,8 +158,8 @@ nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff, blk_opf_t opf,
 	*out_bh = bh;
 
  failed_bh:
-	unlock_page(bh->b_page);
-	put_page(bh->b_page);
+	folio_unlock(bh->b_folio);
+	folio_put(bh->b_folio);
 	brelse(bh);
  failed:
 	return ret;