powerpc/mm: Rename table dump file name

Page table dump debugfs file is named 'kernel_page_tables' on
all other architectures implementing it, while is is named
'kernel_pagetables' on powerpc. This patch renames it.
Signed-off-by: NChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

arch/powerpc/mm/dump_linuxpagetables.c

@@ -513,7 +513,7 @@ static int ptdump_init(void)
 
 	populate_markers();
 	build_pgtable_complete_mask();
-	debugfs_file = debugfs_create_file("kernel_pagetables", 0400, NULL,
+	debugfs_file = debugfs_create_file("kernel_page_tables", 0400, NULL,
 			NULL, &ptdump_fops);
 	return debugfs_file ? 0 : -ENOMEM;
 }