nilfs2: convert nilfs_btnode_abort_change_key to use a folio

Saves one call to compound_head().

Link: https://lkml.kernel.org/r/20231114084436.2755-21-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/btnode.c

@@ -284,7 +284,7 @@ void nilfs_btnode_abort_change_key(struct address_space *btnc,
 
 	if (nbh == NULL) {	/* blocksize == pagesize */
 		xa_erase_irq(&btnc->i_pages, newkey);
-		unlock_page(ctxt->bh->b_page);
+		folio_unlock(ctxt->bh->b_folio);
 	} else {
 		/*
 		 * When canceling a buffer that a prepare operation has